feat: add the database.sql file with instructions to create the database

Author: Victor

database.sql

@@ -0,0 +1,26 @@
+CREATE FUNCTION set_updated_at_timestamp()
+RETURNS TRIGGER AS $$
+BEGIN
+	NEW.updated_at = NOW();
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TABLE users (
+  id SERIAL NOT NULL PRIMARY KEY,
+  name TEXT NOT NULL,
+  email TEXT NOT NULL UNIQUE,
+  created_at TIMESTAMP WITHOUT TIME ZONE NOT NULL DEFAULT (NOW()),
+  updated_at TIMESTAMP WITHOUT TIME ZONE NOT NULL DEFAULT (NOW())
+);
+
+CREATE TABLE products (
+  id SERIAL NOT NULL PRIMARY KEY,
+  description TEXT NOT NULL,
+  user_id INT NOT NULL REFERENCES users (id) ON UPDATE CASCADE ON DELETE CASCADE,
+  created_at TIMESTAMP WITHOUT TIME ZONE NOT NULL DEFAULT (NOW()),
+  updated_at TIMESTAMP WITHOUT TIME ZONE NOT NULL DEFAULT (NOW())
+);
+
+CREATE TRIGGER set_updated_at_timestamp BEFORE UPDATE ON users FOR EACH ROW EXECUTE PROCEDURE set_updated_at_timestamp();
+CREATE TRIGGER set_updated_at_timestamp BEFORE UPDATE ON products FOR EACH ROW EXECUTE PROCEDURE set_updated_at_timestamp();