refactor test comment controller
add hierarchy of controllers
add hierarchy of models
refactor method extract in tests
Merge branch 'feature/controllers_hierarchy' into develop

* feature/controllers_hierarchy:
  refactor method extract in tests
  add hierarchy of models
  add hierarchy of controllers
add picture in post
regenerate simpleform with bootstrap
refactor somethings
Merge branch 'feature/picture_in_post' into develop

* feature/picture_in_post:
  refactor somethings
  regenerate simpleform with bootstrap
  add picture in post
fix comment back to work
add gem wrong; change comment to post_comment in test
add ancestry and nested comments
Merge branch 'feature/nested_comments' into develop

* feature/nested_comments:
  add ancestry and nested comments
  add gem wrong; change comment to post_comment in test
  fix comment back to work
add paging by kaminari gem
add test for action new in coment controler
add showing of post descending by creation date with ransack
add presenter draper
update README.md, add vagrantfile
Update README.md

add endorse badge
Create CONTRIBUTING.md