migrations fix

models.py

@@ -12,13 +12,15 @@ class Channel(Base):
     id = Column(Integer, primary_key=True)
     name = Column(String)
     link = Column(String)
-    admin_id = Column(Integer, ForeignKey('admins.id'))  # если есть таблица admins
+    admin_id = Column(Integer, ForeignKey('admins.id'))
+    buttons = relationship('Button', back_populates='channel')
 
 class Group(Base):
     __tablename__ = 'groups'
     id = Column(Integer, primary_key=True)
     name = Column(String, nullable=False)
     link = Column(String, nullable=False)
+    admin_id = Column(Integer, ForeignKey('admins.id'))
     buttons = relationship('Button', back_populates='group')
 
 class Button(Base):