DB: Přidání vztahu ve směru users->participants

mo/db.py

@@ -240,6 +240,7 @@ class User(Base):
     note = Column(Text, nullable=False, server_default=text("''::text"))
 
     roles = relationship('UserRole', primaryjoin='UserRole.user_id == User.user_id')
+    participants = relationship('Participant', primaryjoin='Participant.user_id == User.user_id')
 
     def full_name(self) -> str:
         return self.first_name + ' ' + self.last_name