Update migration to make color an integer.

bot/models/migrations/005_down__custom_role.sql

@@ -1 +1,8 @@
 ALTER TABLE custom_roles DROP COLUMN user_id;
+
+BEGIN;
+ALTER TABLE custom_roles ADD COLUMN old_color VARCHAR NOT NULL;
+UPDATE custom_roles SET old_color = CAST(color AS VARCHAR);
+ALTER TABLE custom_roles DROP COLUMN color;
+ALTER TABLE custom_roles RENAME COLUMN old_color TO color;
+COMMIT;

bot/models/migrations/005_up__custom_roles.sql

@@ -1 +1,11 @@
 ALTER TABLE custom_roles ADD COLUMN user_id BIGINT;
+
+
+-- Create a temporary column `new_color` and update the table with the values from this table.
+-- Drop the old color column, then rename the new one and set it to non-nullable.
+BEGIN;
+ALTER TABLE custom_roles ADD COLUMN new_color INTEGER NOT NULL;
+UPDATE custom_roles SET new_color = CAST(color AS INTEGER);
+ALTER TABLE custom_roles DROP COLUMN color;
+ALTER TABLE custom_roles RENAME COLUMN new_color TO color;
+COMMIT;