Useful and funny!
However I have to ask why you used a before save event to check the db for duplicates. It would seem that this could create a typical race condition that could possibly result in duplicate entries.
Wouldn’t it be better to set a unique index on the table and use something like a WHERE NOT EXISTS clause? (assuming the DBMS supports SQL)
I would like to hear how you handled this issue. (Curious as I’m a developer myself.)
Also, I wish you good luck with your awesome product!