Handle circular required keys

Use a dummy-value at first and update it later.
Deferrable doesn't seem to work for NOT NULL - only
for FOREIGN KEYs.

postgres/schema/0008_categories.sql

@@ -4,7 +4,8 @@ CREATE TABLE categories (
     category_group_id uuid NOT NULL REFERENCES category_groups (id) ON DELETE CASCADE,
     name varchar(50) NOT NULL
 );
-ALTER TABLE budgets ADD COLUMN income_category_id uuid NOT NULL REFERENCES categories (id) DEFERRABLE;
+ALTER TABLE budgets ADD COLUMN
+    income_category_id uuid NOT NULL REFERENCES categories (id) DEFERRABLE INITIALLY DEFERRED;
 
 -- +goose Down
 ALTER TABLE budgets DROP COLUMN income_category_id;