column_timestamps 0.1.1
Works "automagically" like updated_at...just add a column named _updated_at, and when your column changes, the timestamp will be updated.
          Gemfile:
          =
        
        
          install:
          =
        
      Runtime Dependencies (1):
            activerecord
            >= 2.1.0
          
    Development Dependencies (2):
            rspec
            >= 1.2.9
          
          
            sqlite3-ruby
            >= 1.2.5
          
    