diff --git a/__init__.py b/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/migration.py b/migrations/2024_12_02_005300_create_tables.py
similarity index 99%
rename from migration.py
rename to migrations/2024_12_02_005300_create_tables.py
index f0661f1..504f57e 100644
--- a/migration.py
+++ b/migrations/2024_12_02_005300_create_tables.py
@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from config import CONFIG
+from ..config import CONFIG
 from eloquent import DatabaseManager, Schema
 
 DB = DatabaseManager (CONFIG)
diff --git a/migrations/2024_12_02_005500_create_answered_flags.py b/migrations/2024_12_02_005500_create_answered_flags.py
new file mode 100644
index 0000000..98c4791
--- /dev/null
+++ b/migrations/2024_12_02_005500_create_answered_flags.py
@@ -0,0 +1,34 @@
+from __future__ import annotations
+
+from ..config import CONFIG
+from eloquent import DatabaseManager, Schema
+
+DB = DatabaseManager (CONFIG)
+SCHEMA = Schema (DB)
+
+
+def main (
+) -> None:
+    create_answered_flags ()
+    drop_answered_column_in_answers ()
+
+
+def create_answered_flags (
+) -> None:
+    with SCHEMA.create ('answered_flags') as table:
+        table.big_increments ('id')
+        table.unsigned_big_integer ('answer_id').comment ('回答')
+        table.integer ('platform').comment ('プラットフォーム区分')
+        table.boolean ('answered').default (False).comment ('回答済')
+        table.unique (['answered_id', 'platform'])
+        table.foreign ('answered_id').references ('id').on ('answers').on_update ('cascade').on_delete ('cascade')
+
+
+def drop_answered_column_in_answers (
+) -> None:
+    with SCHEMA.table ('answers') as table:
+        table.drop_column ('answered')
+
+
+if __name__ == '__main__':
+    main ()