Store relations in mysql database

I’m building a database that will be portable from dev to prod, by keeping strictly similar schemas and models with Docker.
Everything is working and transferred, except the associations between the existing entries, that I don’t know how to make persist. Because they are not written is the database when using the Admin panel.
Would you have any advice on how to handle that ? Should I create foreign keys myself on the tables? How can I persist these ?
Thank you,

My bad, they are indeed created and stored in sub tables that hold both name of the linked models. I have mispelled my model when recreating it, hence not finding data. But it works nicely.