Merge pull request #13 from yeonsik/master

following 관련 기능 추가
precompile assets
refactoring
add comments_count to Post
fix migration
add github buttons to footer
add nprogress as bower component
add simple navigation and friendly_id
install public activity & add locale for models
add locales
인덱스에 부트스트랩 입혔습니다.
add default avatar image
edit image size version
일단 인덱스만 부트스트랩 입혀보았습니다.
Merge branch 'bootstrap'
edit upload image version size
Merge remote-tracking branch 'origin/master'
merge with upstream/master
Merge pull request #14 from junheon/master

simple_navigation, friendly_id 등 추가
fix migation error
precompile assets