core: Improve the error for no stock
frontend: Improve the error for no stock
CHANGELOG: Update
core: Imprement validation for stocks
frontend: Fix the default quantity into the cart
Fix a spec for order with no stock
Change error messages and paths
rubocop: Refactor methods
frontend: Change the key of the assignment for flash error
Merge branch 'master' into hotfix/no_stock_error

Conflicts:
	frontend/app/controllers/comable/carts_controller.rb
Merge pull request #37 from hyoshida/hotfix/no_stock_error

Improve no stock error