How to make data from the db into an array

As the title says i need to make a db field into an array the db field
is of the type text and could for an example look like this:

Blues, Elektronisk, Jazz, Klassisk, Metal, Rock

and i can get it by typing @spec.music_style

i need to use it in a for each loop, and tried to do this

<% [@spec.music_style].each do |music_style| %>

but it doesn’t seem to work

Regards Benjamin