adds product model, migration, and association between user, store, and product
syntax change in store/index file
Merge branch 'product_model'
creates products controller
Merge pull request #10 from ageobab/master

test index avail only to store owner, show action available to show view
stores controller
Merge pull request #11 from kelliwarren/store_controller_test

stores controller
merge commit
Merge branch 'store_controller_test' of https://github.com/Mitch24/grocery- into store_controller_test
fixes store_controller_test issues in index describe block