Make tags links
Fix bug with saving a question without tag_list specified
Sort tags by popularity
Sort tags alphabetically
Sort tags by the date of creation
Improve tags controller specs
Edit README
Add profiles for users
Refactor Question.unanswered with counter cache column
Rename scopes of Question model
Add avatars to users
Users have profiles
Improve update_resource method in ApplicationController
Users can change their avatars
Fix default avatar
Fix use_has_profile spec
Optimize votes summing by adding votes_sum column