Created resource routes for grocery lists.  Path for routes is labeled as "list".

Ex:  /lists   =>  grocery_lists#index
Grocery list index route returns all lists for current user.
Grocery List show path created.  Will redirect users to the list index path if the list they are attempting to view does not belong to current user.
Grocery list destroy path done.  #destroy is used so that associated grocery_list_ingredient associations are destroyed as well.

Upon success, users are redirected to grocery_lists_path.
grocery list model changed to make grocery_list_ingredient associations dependent on lists. List destroyed => associations destroyed.
grocery_list#new created.  Users are redirected to root_path unless there is a current_user.
added return statements to show and new actions to stop code execution in the case of redirects.
Merge pull request #10 from ClarkGH/grocery_list_routes

Grocery list routes