🐛 Fix DB Alembic migrations generated password

Author: tiangolo

{{cookiecutter.project_slug}}/backend/app/alembic.ini

@@ -35,7 +35,7 @@ script_location = alembic
 # are written from script.py.mako
 # output_encoding = utf-8
 
-sqlalchemy.url = postgresql://postgres:changethis@db/app
+sqlalchemy.url = postgresql://postgres:{{cookiecutter.postgres_password}}@db/app
 
 
 # Logging configuration