implement database persistence layer and core restaurant backend logic

src/main/java/dev/database/DatabaseConnection.java

@@ -1,27 +1,20 @@
 package dev.database;
 
 import java.sql.Connection;
+import java.sql.DriverManager;
 import java.sql.SQLException;
 
 public class DatabaseConnection {
 
     private static final String URL = "jdbc:postgresql://localhost:5432/restaurant_db"; // DB Server
-
     private static final String USER = "postgres"; // Your Username
-
-    private static final String PASSWORD = "password"; // Your Password
+    private static final String PASSWORD = "password"; // Your Password (اینجا پسورد دیتابیس خودت رو بذار)
 
     private DatabaseConnection() {
-
     }
 
-    public static Connection getConnection()
-            throws SQLException {
-
-        // TODO:
-        // Return a valid PostgreSQL connection
-
-        return null;
+    public static Connection getConnection() throws SQLException {
+        // بازگرداندن یک کانکشن معتبر به PostgreSQL دیتابیس
+        return DriverManager.getConnection(URL, USER, PASSWORD);
     }
-
 }