Refactor command message deletion

PluralKit.Core/Database/Migrations/11.sql

@@ -1,17 +1,10 @@
--- SCHEMA VERSION 11: (insert date) --
+-- SCHEMA VERSION 11: 2020-10-23  --
 -- Create command message table --
 
-create table command_message
+create table command_messages
 (
-	message_id bigint primary key,
-	author_id bigint not null,
-	timestamp timestamp not null default now()
+	message_id bigint primary key not null,
+	author_id bigint not null
 );
 
-create function cleanup_command_message() returns void as $$
-begin
-    delete from command_message where timestamp < now() - interval '2 hours';
-end;
-$$ language plpgsql;
-
 update info set schema_version = 11;