added readme

MIT-LICENSE

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+Copyright (c) 2011 PETER ZHANG
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README

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-Author: Peter Zhang
+h1. Change Log
+
+A gem to keep all maintenances in database
+
+
+h2. Install Change Log Gem
+    1. command:
+    <pre><code># gem install change_log</code</pre>
+
+    2. bundler
+    <pre><code>
+        # Gemfile in your application
+        gem 'change_log','0.0.1'
+    </code</pre>
+    then:
+    <pre><code>
+        bundle install
+    </code</pre>
+
+h2. Create a table to keep all maintenance logs
+
+    1. generate a migration file
+
+    <pre><code>
+        class AddChangeLog < ActiveRecord::Migration
+          def self.up
+            create_table :change_log do |t|
+             t.integer :version, :null=>false # store version of each change
+             t.string :record_id,:limit=>30   # store the actual record id 
+             t.string :table_name, :limti=>60  # store the table name 
+             t.string :attribute_name,:limit=>60 # store the column name
+             t.string :user, :limit=>20  # store the user who made the change
+             t.string :action, :limit=>6 # store the change action: create, read, update, delete
+             t.text :old_value # the value before change
+             t.text :new_value # value after change
+             t.string :field_type, :limit=>30 # the column type eg. date, text, varchar, int etc
+             t.timestamps
+            end
+          end
+
+          def self.down
+            drop_table :change_log
+          end
+        end
+    </code></pre>
+
+    Then:
+    <pre><code>rake db:migrate</code></pre>
+
+h2. Use Change Log
+    1. Add current_user method in application_controller.rb 
+    <pre><code>
+      # used by change log 
+      def current_user # :nodoc:
+        return session[:user] # replace this with your own code to tell change_log who is the current user
+      end
+    </code></pre>
+
+h2. Testing
+    TODO::
+
+
+Author
+------
+
+Peter Zhang at NCS New Zealand.
 Email: peterz@ncs.co.nz
-Description: Keep recording every changes did by user
+
+Copyright (c) 2011 Peter Zhang, released under the MIT license