add replies count with topic in event show view
uesd border-radius mixin with scss
Reproduce the unmatch foreign key bug

Refs #419, #421
Override the foreign_key of GroupTopicReply#topic

Fixed #421, refs #419
Merge pull request #422 from doitian/421-unmatch-foreign-key

421 unmatch foreign key
extend badge class in replies-count class
remove about before_save code because this has fixed in #421
Merge remote-tracking branch 'ywjno/issue_413'

Conflicts:
	app/models/group_topic_reply.rb
Merge remote-tracking branch 'ichord/rails4' into rails4

Do not delete existing migration.

Conflicts:
	db/schema.rb
config: add uglifier as js_compressor in `production.rb`
config: remove some unnecessary config