feat: add is_admin field to User model for role management

app/models.py

@@ -8,6 +8,7 @@ class User(UserMixin, db.Model):
     id = db.Column(db.Integer, primary_key=True)
     email = db.Column(db.String(120), unique=True, nullable=False)
     name = db.Column(db.String(100), nullable=False)
+    is_admin = db.Column(db.Boolean, default=False, nullable=False)
 
 
 class OAuth(OAuthConsumerMixin, db.Model):