feat(api): initial implementation of the auth system (#30)

Adds the auth system but does not add all required features. They will be handled in other tickets

server/middleware/auth.ts

@@ -0,0 +1,29 @@
+import { getRepository } from 'typeorm';
+import { User } from '../entity/User';
+import { Middleware } from '../types/express';
+
+export const checkUser: Middleware = async (req, _res, next) => {
+  if (req.session?.userId) {
+    const userRepository = getRepository(User);
+
+    const user = await userRepository.findOne({
+      where: { id: req.session.userId },
+    });
+
+    if (user) {
+      req.user = user;
+    }
+  }
+  next();
+};
+
+export const isAuthenticated: Middleware = async (req, res, next) => {
+  if (!req.user) {
+    res.status(403).json({
+      status: 403,
+      error: 'You do not have permisson to access this endpoint',
+    });
+  } else {
+    next();
+  }
+};