Added a user system with no proper user validation but working authorisation.

backend/migrations/2022-04-17-175115_user-system/down.sql

@@ -0,0 +1,4 @@
+-- This file should undo anything in `up.sql`
+
+drop table user;
+drop table pwd;

backend/migrations/2022-04-17-175115_user-system/up.sql

@@ -0,0 +1,11 @@
+CREATE TABLE user (
+    id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    username TEXT UNIQUE NOT NULL,
+    email TEXT UNIQUE NOT NULL,
+    role TEXT NOT NULL
+);
+
+CREATE TABLE pwd (
+    id INTEGER NOT NULL PRIMARY KEY,
+    password TEXT NOT NULL
+);