Simple travel planner

• User is able to create an account and log in.
• When logged in, a user can see, edit and delete trips he entered.
• There exists three roles with different permission levels:
  1. A regular user would only be able to CRUD on their owned records
  2. A user manager would be able to CRUD users
  3. An admin would be able to CRUD all records and users.
• When a trip is entered, it has Destination, StartDate, EndDate, Comment.
• User can filter trips. (TODO)
• Print travel plan for next month.
• REST API. Make it possible to perform all user actions via the API, including authentication.