[feature]init Admin page assets
[chore]use stub in assetpipeline to exclude admin.css

Note: [this](https://github.com/sstephenson/sprockets) has the
directives can be used in manifest file
[chore]admin layout
[feature]introduce simple-form for Admin forms
[feature]begin to work on Admin panels
[feature]admin can destroy a card
[chore]redirect to admin dashboard if logged in as Admin
[feature]admin can hide/view card
[chore]refactor admin/albums/index page for hide/view action
[chore]try to make ci pass
[chore]add a file to style/admin/. will remove the file later
[chore]touch .ruby-version file to make CI pass
[chore]modify .travis.yml to add ruby version
[chore]add admin/js file to make CI pass
[feature]init admin users index page
[chore]Admin can delete user
[chore]remove admin/users_controller test to make it pss
Merge pull request #25 from peterzd/admin_panel

Admin panel