Sorted:

Scope of class variable-Collection of common programming errors

Rails 4 + Devise – User.find_by problems-Collection of common programming errors

Cannot Convert String and Fixnum to JSON in Rails 3-Collection of common programming errors

Ruby(HardWay(ex9)) << uninitialized constant PARAGRAPH-Collection of common programming errors

Returning from ruby blocks outside of their original scope-Collection of common programming errors

Error with Gitlab: Sidekiq; gemfile syntax error-Collection of common programming errors

What's wrong with the Square and Rectangle inheritance?-Collection of common programming errors

phonegap android sample project not building-Collection of common programming errors

Rails makevoteable help creating user voting link and custom error message-Collection of common programming errors

FSEvents in MacRuby: wrong callback is executed-Collection of common programming errors