WIP checkpoint: Group + membership models + migration

backend/alembic/versions/0003_add_groups_and_members.py

@@ -20,13 +20,24 @@ depends_on: Union[str, Sequence[str], None] = None
 
 def upgrade() -> None:
     """Create groups and group_members tables."""
+    # Create group_member_role ENUM type
+    group_member_role = postgresql.ENUM(
+        "owner", "admin", "member", name="group_member_role"
+    )
+    group_member_role.create(op.get_bind(), checkfirst=True)
+
     # Create groups table
     op.create_table(
         "groups",
         sa.Column("id", sa.Integer(), primary_key=True, index=True),
         sa.Column("name", sa.String(length=255), nullable=False),
         sa.Column("description", sa.Text(), nullable=True),
-        sa.Column("owner_id", sa.Integer(), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False),
+        sa.Column(
+            "owner_id",
+            sa.Integer(),
+            sa.ForeignKey("users.id", ondelete="CASCADE"),
+            nullable=False,
+        ),
         sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
         sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), onupdate=sa.func.now()),
     )
@@ -34,11 +45,23 @@ def upgrade() -> None:
     # Create group_members table
     op.create_table(
         "group_members",
-        sa.Column("group_id", sa.Integer(), sa.ForeignKey("groups.id", ondelete="CASCADE"), primary_key=True),
-        sa.Column("user_id", sa.Integer(), sa.ForeignKey("users.id", ondelete="CASCADE"), primary_key=True),
+        sa.Column(
+            "group_id",
+            sa.Integer(),
+            sa.ForeignKey("groups.id", ondelete="CASCADE"),
+            primary_key=True,
+        ),
+        sa.Column(
+            "user_id",
+            sa.Integer(),
+            sa.ForeignKey("users.id", ondelete="CASCADE"),
+            primary_key=True,
+        ),
         sa.Column(
             "role",
-            postgresql.ENUM("owner", "admin", "member", name="group_member_role", create_type=False),
+            postgresql.ENUM(
+                "owner", "admin", "member", name="group_member_role", create_type=False
+            ),
             nullable=False,
             default="member",
         ),
@@ -50,3 +73,6 @@ def downgrade() -> None:
     """Drop group_members and groups tables."""
     op.drop_table("group_members")
     op.drop_table("groups")
+
+    # Drop group_member_role ENUM type
+    postgresql.ENUM(name="group_member_role").drop(op.get_bind(), checkfirst=True)