Sequel.migration do
  up do
    alter_table :user_migration_exports do
      drop_constraint :user_migration_exports_log_id_fkey
    end 
    alter_table :user_migration_imports do
      drop_constraint :user_migration_imports_log_id_fkey
    end 
  end 

  down do
    alter_table :user_migration_exports do
      add_foreign_key [:log_id], :logs, null: false
    end 
    alter_table :user_migration_imports do
      add_foreign_key [:log_id], :logs, null: false
    end 
  end 
end


Drop log_id foreign key from user migrations
Drop log_id foreign key from user migrations

The log_id column is still mandatory because all the logic involves
writing a log. However, having a history of the logs of users migrations
is not really needed so, this way, we can implement a retention policy
of the logs while keeping all the users migrations metadata
