diff --git a/.travis.yml b/.travis.yml
index 14de476..2f6c23f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,6 +16,9 @@ after_script:
   - bundle exec rake coveralls:push
 
 install:
-  - gem install bundler
+  - if [ $TRAVIS_RUBY_VERSION == '2.2' ] || [ $TRAVIS_RUBY_VERSION == '2.1' ] || [ $TRAVIS_RUBY_VERSION == '2.0' ];
+    then gem install bundler -v '1.17.3';
+    else gem install bundler;
+    fi
   - gem install rainbow -v '2.2.1'
   - bundle install
diff --git a/README.md b/README.md
index a133240..b1d65ce 100644
--- a/README.md
+++ b/README.md
@@ -115,56 +115,22 @@ HighCharts example :
 # set the library, to plot charts
 Daru::View.plotting_library = :highcharts
 
-# options for the charts
-opts = {
-      chart: {defaultSeriesType: 'line'},
-      title: {
-        text: 'Solar Employment Growth by Sector, 2010-2016'
-        },
-
-      subtitle: {
-          text: 'Source: thesolarfoundation.com'
-      },
-
-      yAxis: {
-          title: {
-              text: 'Number of Employees'
-          }
-      },
-      legend: {
-          layout: 'vertical',
-          align: 'right',
-          verticalAlign: 'middle'
-      },
-
-      plotOptions: {
-          # this is not working. Find the bug
-          # series: {
-          #     pointStart: 43934
-          # }
-      },
-  }
-
-# data for the charts
-series_dt = ([{
-      name: 'Tokyo',
-      data: [7.0, 6.9, 9.5, 14.5, 18.4, 21.5, 25.2, 26.5, 23.3, 18.3, 13.9, 9.6]
-  }, {
-      name: 'London',
-      data: [3.9, 4.2, 5.7, 8.5, 11.9, 15.2, 17.0, 16.6, 14.2, 10.3, 6.6, 4.8]
-  }])
+# Simple line chart
+@line_graph = Daru::View::Plot.new(
+  data=[43934, 52503, 57177, 69658, 97031, 119931, 137133, 154175]
+)
 
-# initialize
-@line_graph = Daru::View::Plot.new(series_dt, opts)
+# to see graph in IRuby noteboook
+@line_graph.show_in_iruby
 
+# to see graph in any ruby web application framework
 # Add this line in your view file, where you want to see you graph in web application. (It will put the html code of the line graph in web page)
-
 <%=raw @line_graph.div %>
 
-# Now refresh the page, you will be able to see your graph.
-
 ```
 
+![Line Graph](https://github.com/shekharrajak/medium-daru-view-blog/blob/master/GIF_Images/HighChartBlog/lineChart.gif)
+
 
 Nyaplot example :
 
diff --git a/lib/daru/view/adapters/datatables.rb b/lib/daru/view/adapters/datatables.rb
index cec4a2c..e8dc265 100644
--- a/lib/daru/view/adapters/datatables.rb
+++ b/lib/daru/view/adapters/datatables.rb
@@ -6,8 +6,6 @@ module Daru
   module View
     module Adapter
       module DatatablesAdapter
-        extend self # rubocop:disable Style/ModuleFunction
-
         # Read : https://datatables.net/ to understand
         # the datatables option concept.
         # Along with these options, a user can provide an additional option
@@ -57,13 +55,13 @@ module DatatablesAdapter
         #     table = Daru::View::Table.new(df_sale_exp, options1)
         #     table2 = Daru::View::Table.new(df_sale_exp, options2)
         #     table3 = Daru::View::Table.new(df_sale_exp)
-        def init_table(data=[], options={}, _user_options={})
+        def self.init_table(data=[], options={}, _user_options={})
           @table = Daru::View::DataTable.new(data, options)
           @table
         end
 
         # @return [String] returns code of the dependent JS and CSS file(s)
-        def init_script
+        def self.init_script
           Daru::View::DataTables.init_script
         end
 
@@ -71,7 +69,7 @@ def init_script
         #   daru-data_table methods
         # @return [String] script and table (containg thead only) tags of the
         #   datatable generated
-        def generate_body(table)
+        def self.generate_body(table)
           table.to_html
         end
 
@@ -81,7 +79,7 @@ def generate_body(table)
         # @example
         #   table = Daru::View::Table.new(data, options)
         #   table.export_html_file
-        def export_html_file(table, path='./table.html')
+        def self.export_html_file(table, path='./table.html')
           path = File.expand_path(path, Dir.pwd)
           str = generate_html(table)
           File.write(path, str)
@@ -93,14 +91,14 @@ def export_html_file(table, path='./table.html')
         # @example
         #   table = Daru::View::Table.new(data, options)
         #   table.show_in_iruby
-        def show_in_iruby(table)
+        def self.show_in_iruby(table)
           table.show_in_iruby
         end
 
         # @param table [Daru::DataTables::DataTable] table object to access
         #   daru-data_table methods
         # @return [String] returns html code of the datatable generated
-        def generate_html(table)
+        def self.generate_html(table)
           path = File.expand_path(
             '../templates/datatables/static_html.erb', __dir__
           )
@@ -115,7 +113,7 @@ def generate_html(table)
         # @example
         #   table = Daru::View::Table.new(data, options)
         #   table.init_iruby
-        def init_iruby
+        def self.init_iruby
           Daru::View::DataTables.init_iruby
         end
       end
diff --git a/lib/daru/view/adapters/googlecharts.rb b/lib/daru/view/adapters/googlecharts.rb
index 30e4574..a2bb0fa 100644
--- a/lib/daru/view/adapters/googlecharts.rb
+++ b/lib/daru/view/adapters/googlecharts.rb
@@ -9,8 +9,6 @@ module Daru
   module View
     module Adapter
       module GooglechartsAdapter
-        extend self # rubocop:disable Style/ModuleFunction
-
         # Read : https://developers.google.com/chart/ to understand
         # the google charts option concept.
         # and google_visualr : http://googlevisualr.herokuapp.com/
@@ -72,7 +70,7 @@ module GooglechartsAdapter
         #   Draw the Daru::View::PlotList object with the data as an array of
         #   Daru::View::Plots(s) or Daru::View::Table(s) or both
         #     combined = Daru::View::PlotList([line_chart, bar_chart])
-        def init(data=[], options={}, user_options={})
+        def self.init(data=[], options={}, user_options={})
           @table = GoogleVisualr::DataTable.new
           @table = get_table(data) unless data.is_a?(String)
           validate_url(data) if data.is_a?(String)
@@ -135,7 +133,7 @@ def init(data=[], options={}, user_options={})
         #         ['2016',  1030,      540]
         #   ]
         #   table = Daru::View::Table.new(data, {}, chart_class: 'Charteditor')
-        def init_table(data=[], options={}, user_options={})
+        def self.init_table(data=[], options={}, user_options={})
           # if `options` is something like this :
           # {
           #   cols: [{id: 'task', label: 'Employee Name', type: 'string'},
@@ -165,7 +163,7 @@ def init_table(data=[], options={}, user_options={})
         #   has to invoked
         # @return [Boolean, void] returns true for valid URL and raises error
         #   for invalid URL
-        def validate_url(data)
+        def self.validate_url(data)
           # `PATTERN_URL.match? data` is faster but does not support older ruby
           #  versions
           # For testing purpose, it is returning true
@@ -174,21 +172,21 @@ def validate_url(data)
           raise 'Invalid URL'
         end
 
-        def init_script
+        def self.init_script
           GoogleVisualr.init_script
         end
 
-        def generate_body(plot)
+        def self.generate_body(plot)
           plot.to_html
         end
 
-        def export_html_file(plot, path='./plot.html')
+        def self.export_html_file(plot, path='./plot.html')
           path = File.expand_path(path, Dir.pwd)
           str = generate_html(plot)
           File.write(path, str)
         end
 
-        def show_in_iruby(plot)
+        def self.show_in_iruby(plot)
           plot.show_in_iruby
         end
 
@@ -198,7 +196,7 @@ def show_in_iruby(plot)
         #     IRuby notebook.
         #
         # @see #Daru::View::Plot.export
-        def export(plot, export_type='png', file_name='chart')
+        def self.export(plot, export_type='png', file_name='chart')
           raise NotImplementedError, 'Not yet implemented!' unless
           export_type == 'png'
 
@@ -207,7 +205,7 @@ def export(plot, export_type='png', file_name='chart')
           plot.export(export_type, file_name)
         end
 
-        def generate_html(plot)
+        def self.generate_html(plot)
           path = File.expand_path(
             '../templates/googlecharts/static_html.erb', __dir__
           )
@@ -218,13 +216,13 @@ def generate_html(plot)
           ERB.new(template).result(binding)
         end
 
-        def init_iruby
+        def self.init_iruby
           GoogleVisualr.init_iruby
         end
 
         # Generally, in opts Hash, :name, :type, :data , :center=> [X, Y],
         # :size=> Integer, :showInLegend=> Bool, etc may present.
-        def add_series(plot, opts={})
+        def self.add_series(plot, opts={})
           plot.series(opts)
           plot
         end
@@ -237,7 +235,7 @@ def add_series(plot, opts={})
         #   from which data has to invoked
         # @return [GoogleVisualr::DataTable] the table object with the data
         #   filled
-        def get_table(data)
+        def self.get_table(data)
           if data.is_a?(Daru::View::Table) &&
              data.table.is_a?(GoogleVisualr::DataTable)
             data.table
@@ -248,7 +246,7 @@ def get_table(data)
           end
         end
 
-        def extract_chart_type(options)
+        def self.extract_chart_type(options)
           # TODO: Imprvoe this method.
           chart_type = options[:type].nil? ? 'Line' : options.delete(:type)
           chart_type = chart_type.to_s.capitalize
@@ -265,7 +263,7 @@ def extract_chart_type(options)
         #
         # TODO : Currently I didn't find use case for multi index.
         # rubocop:disable Metrics/MethodLength
-        def add_data_in_table(data_set)
+        def self.add_data_in_table(data_set)
           case
           when data_set.is_a?(Daru::DataFrame)
             return ArgumentError unless data_set.index.is_a?(Daru::Index)
@@ -288,7 +286,7 @@ def add_data_in_table(data_set)
         end
         # rubocop:enable Metrics/MethodLength
 
-        def add_dataframe_data(data_set)
+        def self.add_dataframe_data(data_set)
           rows = data_set.access_row_tuples_by_indexs(*data_set.index.to_a)
           data_set.vectors.to_a.each do |vec|
             @table.new_column(converted_type_to_js(vec, data_set), vec)
@@ -296,7 +294,7 @@ def add_dataframe_data(data_set)
           rows
         end
 
-        def add_array_data(data_set)
+        def self.add_array_data(data_set)
           data_set[0].each_with_index do |col, indx|
             # TODO: below while loop must be improved. Similar thing for
             # above 2 cases.
@@ -312,7 +310,7 @@ def add_array_data(data_set)
           data_set
         end
 
-        def add_vector_data(data_set)
+        def self.add_vector_data(data_set)
           vec_name = data_set.name.nil? ? 'Series' : data_set.name
           @table.new_column(return_js_type(data_set[0]), vec_name)
           rows = []
@@ -320,7 +318,7 @@ def add_vector_data(data_set)
           rows
         end
 
-        def converted_type_to_js(vec_name, data_set)
+        def self.converted_type_to_js(vec_name, data_set)
           # Assuming all the data type is same for all the column values.
           case
           when data_set.is_a?(Daru::DataFrame)
@@ -330,14 +328,14 @@ def converted_type_to_js(vec_name, data_set)
           end
         end
 
-        def return_js_type(data)
+        def self.return_js_type(data)
           return if data.nil?
 
           data = data.is_a?(Hash) ? data[:v] : data
           extract_js_type(data)
         end
 
-        def extract_js_type(data)
+        def self.extract_js_type(data)
           case
           when data.is_a?(String)
             'string'
diff --git a/lib/daru/view/adapters/highcharts.rb b/lib/daru/view/adapters/highcharts.rb
index 22261aa..7fc1a18 100644
--- a/lib/daru/view/adapters/highcharts.rb
+++ b/lib/daru/view/adapters/highcharts.rb
@@ -8,8 +8,6 @@ module Daru
   module View
     module Adapter
       module HighchartsAdapter
-        extend self # rubocop:disable Style/ModuleFunction
-
         # Read : https://www.highcharts.com/docs/chart-concepts to understand
         # the highcharts option concept.
         #
@@ -28,7 +26,7 @@ module HighchartsAdapter
         #
         # @param [Array/Daru::DataFrame/Daru::Vector] data
         #
-        def init(data=[], options={}, user_options={})
+        def self.init(data=[], options={}, user_options={})
           # Alternate way is using `add_series` method.
           #
           # There are many options present in Highcharts so it is better to use
@@ -57,15 +55,15 @@ def init(data=[], options={}, user_options={})
           @chart
         end
 
-        def init_script
+        def self.init_script
           LazyHighCharts.init_script
         end
 
-        def generate_body(plot)
+        def self.generate_body(plot)
           plot.to_html
         end
 
-        def export_html_file(plot, path='./plot.html')
+        def self.export_html_file(plot, path='./plot.html')
           path = File.expand_path(path, Dir.pwd)
           str = generate_html(plot)
           File.write(path, str)
@@ -80,17 +78,17 @@ def export_html_file(plot, path='./plot.html')
         #   running the cells works fine.
         #
         # @see #Daru::View::Plot.export
-        def export(plot, export_type='png', file_name='chart')
+        def self.export(plot, export_type='png', file_name='chart')
           plot.export_iruby(export_type, file_name) if defined? IRuby
         rescue NameError
           plot.export(export_type, file_name)
         end
 
-        def show_in_iruby(plot)
+        def self.show_in_iruby(plot)
           plot.show_in_iruby
         end
 
-        def generate_html(plot)
+        def self.generate_html(plot)
           path = File.expand_path('../templates/highcharts/static_html.erb', __dir__)
           template = File.read(path)
           initial_script = init_script
@@ -98,20 +96,20 @@ def generate_html(plot)
           ERB.new(template).result(binding)
         end
 
-        def init_iruby
+        def self.init_iruby
           LazyHighCharts.init_iruby
         end
 
         # Generally, in opts Hash, :name, :type, :data , :center=> [X, Y],
         # :size=> Integer, :showInLegend=> Bool, etc may present.
-        def add_series(plot, opts={})
+        def self.add_series(plot, opts={})
           plot.series(opts)
           plot
         end
 
         private
 
-        def guess_data(data_set)
+        def self.guess_data(data_set)
           case
           when data_set.is_a?(Daru::DataFrame)
             # TODO : Currently I didn't find use case for multi index.
diff --git a/lib/daru/view/adapters/nyaplot.rb b/lib/daru/view/adapters/nyaplot.rb
index 50422b2..b9e12bd 100644
--- a/lib/daru/view/adapters/nyaplot.rb
+++ b/lib/daru/view/adapters/nyaplot.rb
@@ -6,43 +6,42 @@ module Daru
   module View
     module Adapter
       module NyaplotAdapter
-        extend self # rubocop:disable Style/ModuleFunction
-        def init(data, options, _user_options={})
+        def self.init(data, options, _user_options={})
           data_new = guess_data(data)
           data_new.plot(options)
         end
 
-        def export_html_file(plot, path)
+        def self.export_html_file(plot, path)
           plot.export_html path
         end
 
-        def export(_plot, _export_type='png', _file_name='chart')
+        def self.export(_plot, _export_type='png', _file_name='chart')
           raise 'Not implemented yet'
         end
 
-        def show_in_iruby(plot)
+        def self.show_in_iruby(plot)
           plot.show
         end
 
-        def init_script
+        def self.init_script
           Nyaplot.init_script
         end
 
-        def generate_body(plot)
+        def self.generate_body(plot)
           plot.to_iruby[1]
         end
 
-        def init_iruby
+        def self.init_iruby
           Nyaplot.init_iruby
         end
 
         private
 
-        def multi_dimension_check(arr)
+        def self.multi_dimension_check(arr)
           arr.all? { |a| a.class==Array }
         end
 
-        def guess_data(data_set)
+        def self.guess_data(data_set)
           case
           when [Daru::DataFrame, Daru::Vector].include?(data_set.class)
             data_set