add .DS_Store to gitignore
refactor ingredient calculations
Create GroceryList model and move total calculation from User to GroceryList
resolve merge conflicts
Combine items in grocery list if same product
Remove unused method 'total' from User model
Update tests to reflect factory changes
Merge pull request #36 from purple-martins-2013/combine_items_in_grocery_list_if_same_product

Combine items in grocery list if same product