Rails 4.1.2, Mongoid 4.0.0
Migrate to RSpec 3 and eliminate all deprecations

* Add RSpec 3.x rails_helper and spec_helper conventions
* Use the `expect` syntax over the old `should` syntax
* Use the `allow` syntax over the old `mock` syntax
* Remove `visit` in controller specs
* Change :example_group filtering
* Change `expect(record).not_to have(1).error_on(:slug)` syntax
* w/ capybara upgraded from `0.2` to `2.3`
* w/ cancan upgraded to `cancancan`
Merge pull request #323 from pmq20/upgrading_rspec_23

Migrate to RSpec 3 and eliminate all deprecations
Fix #320

Same validation logic on email could be found
at Line 29 to 31 of Devise::Models::Validatable.

Therefore validates_presence_of :email
in application code is not necessary.
Merge pull request #324 from pmq20/master

Fix #320
Use Rails 4.1.4

* w/ assets.rb created in the spirit of rails/rails#14689
Merge pull request #325 from pmq20/master

Use Rails 4.1.4
Fix typo :grin:
Merge pull request #326 from haio/master

Fix typo :grin:
Upgrade auto-space
Merge branch 'master' of github.com:ruby-china/ruby-china
后台微调;
Github -> GitHub
某些错误的空格、拼写修正;
update _topic.html.erb to auto expire cache.
.
Wiki page style updated, auto-space upgrade 0.0.4;
.
将引号统一修改为单引号
Merge pull request #327 from diguage/master

将引号统一修改为单引号