diff --git a/db/migration/000001_init_schema.up.sql b/db/migration/000001_init_schema.up.sql
index 0fda177..ba86b12 100644
--- a/db/migration/000001_init_schema.up.sql
+++ b/db/migration/000001_init_schema.up.sql
@@ -6,7 +6,7 @@ CREATE TABLE "mails" (
   "timestamp" timestamptz NOT NULL DEFAULT (now()),
   "subject" varchar NOT NULL,
   "body" text NOT NULL,
-  "attachments" integer
+  "attachments" bigserial
 );
 
 CREATE TABLE "customers" (