add efficient filesystem handling for guard
Revert "add efficient filesystem handling for guard"

This reverts commit 6ba615c5866021a30d6b2c50ae33044b180dd14b.
Merge branch 'official'
Merge branch 'official'
update readme.
Merge branch 'master' of github.com:saberma/19wu
wear coveralls.
update gem: rails, devise, mini_magick
use gemnasium to monitor gem security.
handle-unauthorized-access
add I18n for cancan
remove unauthorized/manage from locales
modify the redirect when CanCan::AccessDenied
use middleware to redirect old event slug. close #305
Merge pull request #322 from caok/issue/318-handle-unauthorized-access

Issue/318 handle unauthorized access
Merge pull request #317 from saberma/saberma-enhancement/wear-coveralls

显示 coveralls.io 测试覆盖率
merge.
non-freshing join
1,redirect to login page while click "join" button.
2, refresh count of joined.

know issue:
  1, while no guys joined an event, this first guy click "join" button, the "Joined guys" section should not shown.
  2, avatar section could not refresh after someone joined.
1, cancel a joined event.
2, read tooltip text from i18n.
优化代码