generate comment model
add validations to comment model
establish 1:n relationship between post and comment models
create comments controller (copied from posts controller - probably still needs some changes)
add comment routes to routes.rb (preliminary)
add comment routes to router.js
create comment.js (model)
extend seeds.rb (comments for first post)
create comments_controller.js
introduce dependy of post_controller.js on comments_controller.js
establish 1:n relationship between post.js and comment.js models
start integrating display of comments into post template (preliminary)