added factory_girl gem
added user factory
added factory for posts_controller test
mixed FactoryGirl methods
added comments factory
added sequences for FactoryGirl
added user factory for comments_controller test
Merge branch 'factory_girl' into develop

* factory_girl:
  added user factory for comments_controller test
  added sequences for FactoryGirl
  added comments factory
  mixed FactoryGirl methods
  added factory for posts_controller test
  added user factory
  added factory_girl gem