move queries to db folder, change database to better accommodate musicbrainz api data

db/queries/users.sql

@@ -0,0 +1,17 @@
+-- users.sql
+-- name: CreateUser :one
+INSERT INTO users (id, user_name, user_mail, password) VALUES ($1, $2, $3, $4) RETURNING id;
+
+-- name: UpdateUser :exec
+UPDATE users SET user_name = $2, user_mail = $3, password = $4 WHERE id = $1;
+
+-- name: GetUsernameByID :one
+SELECT user_name FROM users WHERE id = $1;
+
+-- name: GetUserByID :one
+SELECT id, user_name, user_mail, created_at FROM users WHERE id = $1;
+
+-- name: GetUserAuthByEmail :one
+SELECT id, user_name, user_mail, password
+FROM users
+WHERE user_mail = $1;