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.
Merge pull request #324 from saberma/saberma-enhancement/305-group-slug-rename-middleware

访问旧活动地址时要跳转到新的地址（改用 middleware 实现）. #305