API docs

/tags
  GET         - returns all tags in db
  POST        - adds a new tag to db

/cards
  GET         - returns all cards in db
  POST        - adds a new card to db
/cards/:id
  GET         - returns details for card of :id
  PUT         - updates details for card of :id
  DELETE      - deletes card of :id

todos

• Move to RoR or Sinatra
• Use RDMS for cards
• Write WebSockets for sync between users