Change for specs
order test finished
Add order in. Add relevant tests in.
Add upward and downward method. Add relavent tests.
merge to master
Merge branch 'feature/category_order'
Generate posts and topics.
Topics and relative tests are finished
Add spec/factories/topic.rb
modify topics_controller.rb to keep conssistent
Merge pull request #3 from KevinXuxuxu/feature/post_and_topic

Feature/post and topic
Add comments and its tests. Some bugs are there
Bug fixed
Fix some rspec tests
Add files in
Rename the comments views for partial
Fix some problems for rspec tests
comment system finished
add a test for comment
finishd replying replies