install gem http_accept_language to help extract http accept language header
internationalization concern to set current locale
add zh-CN locale template, so that I18n.available_locales will have zh-CN
internationalization specs
Merge pull request #30 from coursemology-collab/wangqiang/i18n

internationalization
install gem simple_form
rails generate simple_form:install --bootstrap
Merge pull request #29 from coursemology-collab/wangqiang/simple_form

simple form
install gem userstamp
update schema_plus, so that the arguments will not change
add userstamps(updater_id) to courses
setup models to use userstamp
include userstamp in application controller
so that the User.stamper will automatically set to current_user
update factories because we added updater_id
rails generate courses controller
default empty actions and routes
new and create action
edit and update action
i18n translation for courses controller