beef up Rakefile tasks set

result :
> rake -T
rake build         # Build sentiment_analysis-0.0.1.gem into the pkg directory
rake clobber_rcov  # Remove rcov products for rcov
rake clobber_rdoc  # Remove RDoc HTML files
rake install       # Build and install sentiment_analysis-0.0.1.gem into system gems
rake rcov          # Run specs using RCov
rake rdoc          # Build RDoc HTML files
rake release       # Create tag v0.0.1 and build and push sentiment_analysis-0.0.1.gem to Rubygems
rake rerdoc        # Rebuild RDoc HTML files
rake spec          # Run specs

Rakefile

@@ -1 +1,22 @@
-require "bundler/gem_tasks"
+# encoding: UTF-8
+require 'bundler'
+Bundler::GemHelper.install_tasks
+
+require 'rake'
+
+require 'spec/rake/spectask'
+Spec::Rake::SpecTask.new(:spec) do |spec|
+  spec.libs << 'lib' << 'spec'
+  spec.spec_files = FileList['spec/**/*_spec.rb']
+end
+task :default => :spec
+
+Spec::Rake::SpecTask.new(:rcov) do |spec|
+  spec.libs    << 'lib' << 'spec'
+  spec.pattern = 'spec/**/*_spec.rb'
+  spec.rcov    = true
+end
+
+require 'rdoc/task'
+RDoc::Task.new do |rdoc|
+end