fixed bug with spreadsheet import

backend/app/database.py

@@ -3,7 +3,7 @@ from sqlalchemy.orm import Session
 from sqlalchemy import create_engine
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import sessionmaker
-from app import models
+from . import models
 import os
 
 # Get username and password from environment variables
@@ -31,12 +31,12 @@ def get_db():
 
 def init_db():
     # Import models inside function to avoid circular dependency
-    from app import models
+    from . import models
     Base.metadata.create_all(bind=engine)
 
 def load_sample_data(session: Session):
     # Import models inside function to avoid circular dependency
-    from app.data import contacts, return_addresses, dewars, proposals, shipments, pucks, samples, dewar_types, serial_numbers, slots, sample_events
+    from .data import contacts, return_addresses, dewars, proposals, shipments, pucks, samples, dewar_types, serial_numbers, slots, sample_events
 
     # If any data already exists, skip seeding
     if session.query(models.ContactPerson).first():