Meal Endpoint: POST /api/v1/meals/:meal_id/foods/:id

[squeemishly]

POST /api/v1/meals/:meal_id/foods/:id - adds the food with :id to the meal with :meal_id
This creates a new record in the MealFoods table to establish the relationship between this food and meal. If the meal/food cannot be found, a 404 will be returned.