docs(db): fix sql comments (#260)

Author: 0xmountaintop

database/migrate/migrations/00002_l1_message.sql

@@ -20,7 +20,7 @@ create table l1_message
 );
 
 comment
-on column l1_message.status is 'undefined, pending, submitted, confirmed, expired';
+on column l1_message.status is 'undefined, pending, submitted, confirmed, failed, expired';
 
 create unique index l1_message_hash_uindex
 on l1_message (msg_hash);

database/migrate/migrations/00003_l2_message.sql

@@ -21,7 +21,7 @@ create table l2_message
 );
 
 comment
-on column l2_message.status is 'undefined, pending, submitted, confirmed, expired';
+on column l2_message.status is 'undefined, pending, submitted, confirmed, failed, expired';
 
 create unique index l2_message_hash_uindex
 on l2_message (msg_hash);