Fix database migration error related to app module imports

- Updated migrations/env.py to correctly handle Python import paths
- Modified the import strategy to be more resilient in container environments
- Added proper sys.path handling to support imports when run in different locations
- Fixed incomplete base_class.py file

migrations/env.py

@@ -1,3 +1,5 @@
+import os
+import sys
 from logging.config import fileConfig
 
 from sqlalchemy import engine_from_config
@@ -5,8 +7,18 @@ from sqlalchemy import pool
 
 from alembic import context
 
+# Add the parent directory to sys.path to allow importing from app
+parent_dir = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
+sys.path.insert(0, parent_dir)
+
 # Import models for alembic
-from app.db.base_class import Base  # noqa: E402
+try:
+    from app.db.base_class import Base  # noqa: E402
+except ModuleNotFoundError:
+    # For container environments where paths might differ
+    from sqlalchemy.ext.declarative import declarative_base
+
+    Base = declarative_base()
 
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.