move models in seperate modules

app/models/token.py

@@ -0,0 +1,48 @@
+from datetime import datetime, timedelta
+from app import db
+
+
+class Token(db.Model):
+    __tablename__ = 'tokens'
+    # Primary key
+    id = db.Column(db.Integer, primary_key=True)
+    # Foreign keys
+    user_id = db.Column(db.Integer, db.ForeignKey('users.id'))
+    # Fields
+    access_token = db.Column(db.String(64), index=True)
+    access_expiration = db.Column(db.DateTime)
+    refresh_token = db.Column(db.String(64), index=True)
+    refresh_expiration = db.Column(db.DateTime)
+    # Relationships
+    user = db.relationship('User', back_populates='tokens')
+
+    def expire(self):
+        self.access_expiration = datetime.utcnow()
+        self.refresh_expiration = datetime.utcnow()
+
+    def to_json_serializeable(self, backrefs=False, relationships=False):
+        json_serializeable = {
+            'id': self.hashid,
+            'access_token': self.access_token,
+            'access_expiration': (
+                None if self.access_expiration is None
+                else f'{self.access_expiration.isoformat()}Z'
+            ),
+            'refresh_token': self.refresh_token,
+            'refresh_expiration': (
+                None if self.refresh_expiration is None
+                else f'{self.refresh_expiration.isoformat()}Z'
+            )
+        }
+        if backrefs:
+            json_serializeable['user'] = \
+                self.user.to_json_serializeable(backrefs=True)
+        if relationships:
+            pass
+        return json_serializeable
+
+    @staticmethod
+    def clean():
+        """Remove any tokens that have been expired for more than a day."""
+        yesterday = datetime.utcnow() - timedelta(days=1)
+        Token.query.filter(Token.refresh_expiration < yesterday).delete()