user has ability to suggest to admin

First decide what the user interface should look like for the user and
the admin. Perhaps you already know that.

Next decide what data must be saved when the user suggests a recipe -
perhaps he just adds a recipe into the table with a flag to say that
it has not been reviewed by the admin yet.

Next write the automated tests for what should happen.

Write the code to migrate the database, for the user to add the recipe
and the admin to review and release it (which may just be a matter of
setting the 'reviewed' flag).