they use sequelize migrations for now, eventually we may want to go to something more advanced. take a backup, apply migrations has worked so far. force sync extremely harmful, sequelize is terrible for not being able to incrementally do schema changes. I don't think it can actually add a column, for example.
For us, as a result, it means anytime we add a new model or change a table, we write the table definition in more verbose api, and sometimes resort to sql commands for adding things like defaults in the migrations. (sequelize for some reason can not specify uuid default value for postgres, for example, so we set a default ourselves, even though we don't need one as we have time dependent uuid generator on the client to help with indices).
We kind of learned working around sequelize shortcomings :)
I am still looking for a tool that'd make incremental backups on postgres easier than it is, but for now things are ok.