Initialize comable_backend

rails plugin new comable_backend --mountable --skip-test-unit -d=postgresql
backend: Change the namespace

comable_backend => comable/admin
backend: Add controller for admin/products

rails generate controller admin/products index
backend: Add routes
backend: html.erb => slim
backend: Implement products index
backend: rubocop: Clean up codes
backend: Change the namespaces

ComableBackend => Comable::Backend
backend: Remove isolate_namespace method
backend: Implement to work tests
backend: gem: rails 4.1.4 => 3.2.0
Add a default task to test the backend
Fix to work fine for Coveralls
Summarize depended gems to a common file
Merge pull request #25 from hyoshida/feature/backend

Implement backend