Signup login and auth middleware

[Reinoptland]

What this pullrequest does:

• Adds endpoints for /signup, /login, /me and /authorized_post_request
• Adds the auth middleware (used in GET /me and POST /authorized_post_request)
• Adds some sample requests with axios & httpie
• Updated readme so this info is easy to find

Adds the following endpoints

Method	Path	Purpose	required parameters	auth
POST	'/signup'	Create a new user and get a token	email, name, password	no
POST	'/login'	Get a token with email & password	email, password	no
GET	'/me'	Get information of this user	none	yes
POST	'/authorized_post_request'	Test POST requests (token required)	none	yes