fix: drop superfluous column in usergroups

Group org is assigned in the Group table. Also assigning it in the UserGroups table complicated relationship creation and it was never used.

.alembic/versions/2026-05-29_drop_user_groups_org_column.py

@@ -0,0 +1,34 @@
+"""Drop user_groups org column
+
+Revision ID: d9dc6986fe38
+Revises: 8132c4b88665
+Create Date: 2026-05-29 16:10:00.320982
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'd9dc6986fe38'
+down_revision: Union[str, Sequence[str], None] = '8132c4b88665'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_constraint(op.f('user_groups_org_id_fkey'), 'user_groups', type_='foreignkey')
+    op.drop_column('user_groups', 'org_id')
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('user_groups', sa.Column('org_id', sa.INTEGER(), autoincrement=False, nullable=False))
+    op.create_foreign_key(op.f('user_groups_org_id_fkey'), 'user_groups', 'organisation', ['org_id'], ['id'], ondelete='CASCADE')
+    # ### end Alembic commands ###

src/iam/models.py

@@ -78,6 +78,5 @@ class GroupPermissions(Base):
 
 class UserGroups(Base):
 	__tablename__ = "user_groups"
-	org_id = Column(Integer, ForeignKey("organisation.id", ondelete="CASCADE"), primary_key=True)
 	user_id = Column(Integer, ForeignKey("user.id", ondelete="CASCADE"), primary_key=True)
 	group_id = Column(Integer, ForeignKey("group.id", ondelete="CASCADE"), primary_key=True)