services/__init__.pyを作成

app/models/workout.py

@@ -1,3 +1,6 @@
+from . import db
+from datetime import datetime
+
 class User(db.Model):
     __tablename__ = 'users'
 

app/services/__init__.py

@@ -0,0 +1,2 @@
+from app.repositories.workout_repository import WorkoutRepository
+from app.models.workout import Workout