Add where_tag scope to Question model
Add show_by_tag action to Questions controller
Show questions by tag name
Add new target to README
Improve HTML for file uploading section on new question page
Fix attach_files_to_questions spec
Add multiple files uploading to answers
Make remove uploaded file feature (for question)
Make remove uploaded file feature (for answer)
Fix attachments controller spec
Update attachments list after editing question
Update attachments list after editing answer