Write signup route and controller to create user

Add middleware for auth if confidant.

Please see swagger docs for guidance.

Set up swagger

Please add ;

--src
--db
connection.js
--user
model.js

Install packages sequelize mysql2 to dependencies

Install nodemon to dev dependencies

Add db connection to src/db/connection.js

Add user model to src/user/model.js

Please make branch from issue, with dev as the source branch.

-> Write middleware to check that the username is unique before creating a user
-> Write middleware to check password follows criteria

Write swagger docs for signup route to conform to given standards shown in Discord - specific doc to follow.