Implement basic user endpoint

[kyrivanderpoel]

I implemented a basic user endpoint. The instructions to run are detailed in the README.md. Please ask for any questions!

The routes implemented thusfar are:

GET /api/v1/users - gets all users
POST /api/v1/users - create a new user
GET /api/v1/users/{email} - get user with the specified email

[JordanRushing]

You should create a comment informing the purpose of db.json here

[JordanRushing]

Alphabetize dependencies here

[JordanRushing]

No exception handling here or on Post.

Try . . .

begin
  # user = users.find . . .
rescue => e
  # return exception / response code here 

[JordanRushing]

Try like this according to Roda best practices:

# config.ru -- configuration file for rackup
require_relative './app'

map '/' do
  run App.freeze.app
end

[JordanRushing]

Added some comments -- Also I like alphabetized dependencies.

Also add logging since you're importing the logger!