Add the comment model!

• Make our errors go away!
• Display comments on campground show page

Comment New/Create

1. Discuss nested routes
2. Add the comment new and create routes
3. Add the new comment form

RESTFUL ROUTES

NAME	URL	VERB	DESCRIPTION
index	/dogs	GET	display a list of all dogs
NEW	/dogs/new	GET	display form to make a new dog
CREATE	/dogs	POST	add new dog to DB
SHOW	/dogs/:id	GET	show info about one dog

NEW COMMENTS ROUTES

NAME	URL	VERB
NEW	campgrounds/:id/comments/new	GET
CREATE	campgrounds/:id/comments	POST