Add a route to request user details

[richchurcher]

We need a way to get the user's information, particularly their role (admin or user) from the server.

• Add a route and database functions to implement the following route:

GET /api/v1/currentuser

It should return something like the following:

{
  "id": "12345",
  "role": "administrator"
}

• To get this information, you'll have to protect the route using express-jwt. This will place a user id (which it gets from the access token) on req.user.sub ('sub' is short for subject, in other words the user).

Ask for help from @richchurcher early on this one! Don't forget to write a test or two 😎 .