diff --git a/backend/app/__init__.py b/backend/app/__init__.py
index 4002ef0..9ce677b 100644
--- a/backend/app/__init__.py
+++ b/backend/app/__init__.py
@@ -1,5 +1,6 @@
 import os
 from flask import Flask, send_from_directory
+from sqlalchemy import text
 from .extensions import db, migrate, cors
 from config import config
 
@@ -21,6 +22,7 @@ def create_app(config_name=None):
 
     with app.app_context():
         db.create_all()
+        _run_migrations()
 
     @app.route('/', defaults={'path': ''})
     @app.route('/<path:path>')
@@ -31,3 +33,22 @@ def create_app(config_name=None):
         return send_from_directory(static_folder, 'index.html')
 
     return app
+
+
+def _run_migrations():
+    """
+    Safe idempotent migrations for existing databases.
+    ALTER TABLE is a no-op if the column already exists (exception silently caught).
+    Add new columns here as the schema evolves.
+    """
+    migrations = [
+        'ALTER TABLE projects ADD COLUMN drive_url VARCHAR(500)',
+    ]
+    with db.engine.connect() as conn:
+        for stmt in migrations:
+            try:
+                conn.execute(text(stmt))
+                conn.commit()
+            except Exception:
+                # Column already exists — safe to ignore
+                pass