Fixed imports

app.py

 from flask import Flask, render_template
 import RPi.GPIO as GPIO
 from flask_sqlalchemy import SQLAlchemy
-from .daily_usage import DailyUsage
+from daily_usage import DailyUsage
 
 app = Flask(__name__)
 app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///energyUsage'

daily_usage.py

-from .app import db
-
+from app import db
 
 class DailyUsage(db.Model):
     id = db.Column(db.Integer, primary_key=True, autoincrement=True)