Use a volume for migrations

migrations/0001-add-appeals.sql

@@ -0,0 +1,16 @@
+--------------------------------------------------------------------------------
+-- Up
+--------------------------------------------------------------------------------
+ALTER TABLE settings ADD appeals_channel_id TEXT;
+
+CREATE TABLE appeals (
+  id INTEGER PRIMARY KEY,
+  message_id TEXT NOT NULL
+);
+
+--------------------------------------------------------------------------------
+-- Down
+--------------------------------------------------------------------------------
+ALTER TABLE settings DROP COLUMN appeals_channel_id;
+
+DROP TABLE appeals;