feat: unlock in-game galleries per owned version

backend/migrations/versions/0007_version_gallery.py

@@ -0,0 +1,15 @@
+"""Opt-in unlocked in-game galleries, scoped to one version."""
+import sqlalchemy as sa
+from alembic import op
+
+revision = "0007"
+down_revision = "0006"
+branch_labels = depends_on = None
+
+
+def upgrade():
+    op.add_column("game_versions", sa.Column("gallery_unlocked", sa.Boolean(), nullable=False, server_default=sa.false()))
+
+
+def downgrade():
+    op.drop_column("game_versions", "gallery_unlocked")