fix: 과제 상태 추가하는 flyway 추가

Author: lilyyang0077

backend/src/main/resources/db/migration/V12__update_assignment_item_submitted_check.sql

@@ -0,0 +1,16 @@
+ALTER TABLE assignment_item
+    DROP CONSTRAINT chk_assignment_item_submitted;
+
+ALTER TABLE assignment_item
+    ADD CONSTRAINT chk_assignment_item_submitted
+        CHECK (
+            submitted IN (
+                          'SUCCESS',
+                          'INSUFFICIENT_MINOR',
+                          'INSUFFICIENT_15000',
+                          'INSUFFICIENT_MAJOR',
+                          'INSUFFICIENT_25000',
+                          'FAILURE',
+                          'PENDING'
+                )
+            );