ActiveResource::Collection is giving NameError

I am trying to run ActiveResource::Collection on console, but its giving name error. Kindly give me a solution to solve this.

 NameError: uninitialized constant ActiveResource::Collection
 from (irb):10
 from /var/lib/gems/2.1.0/gems/railties-3.2.17/lib/rails/commands/console.rb:47:in `start'
 from /var/lib/gems/2.1.0/gems/railties-3.2.17/lib/rails/commands/console.rb:8:in `start'
 from /var/lib/gems/2.1.0/gems/railties-3.2.17/lib/rails/commands.rb:41:in `<top (required)>'
 from script/rails:6:in `require'
 [![enter image description here][1]][1]from script/rails:6:in `<main>'