fix(tables-schema): add missing fields to tables

- add food_image column to menu table
- add unique constraint on email column in users table

[Fixes #160876037]

server/db/schema.sql

@@ -1,14 +1,15 @@
 CREATE TABLE IF NOT EXISTS users (
   id serial PRIMARY KEY,
   name VARCHAR(50) NOT NULL,
-  email VARCHAR(50) NOT NULL,
+  email VARCHAR(50) UNIQUE NOT NULL,
   password VARCHAR(255) NOT NULL,
   is_admin BOOLEAN NOT NULL
 );
 
 CREATE TABLE IF NOT EXISTS menu (
   id serial PRIMARY KEY,
   food_name VARCHAR(255) NOT NULL,
+  food_image VARCHAR(255) NOT NULL DEFAULT 'https://i.imgur.com/yRLsidK.jpg',
   price REAL NOT NULL
 );