Laravel 5 save ids from table in one column

How will you be able to insert ids from other table to one column on another table?

Ex:

table_a a_id a_name

table_b b_id b_car a_id

Is it possible to save multiple ids to table_b.a_id from table_a.a_id in Laravel? I think this has to be related in hasMany but I'm not too familiar in laravel. Thank you.

via Chebli Mohamed