ruby - Rails associations for mailing list -

i want create mailings mailing lists.

users belong mailing lists , mailing lists have many users.

i'm having trouble creating multiple inputs users display list_names , save list_ids.

i have code:

  .form-group     =u.label :mailing_list_id, :class => "col-sm-2 control-label"     .col-sm-10       = u.association :mailing_list, :label => false , :input_html => { :class => 'form-control' } 

it doesn't save changes.

i changed code to:

  .form-group     =u.label :mailing_list_id, :class => "col-sm-2 control-label"     .col-sm-10       = u.collection_select :mailing_list_id, mailinglist.all, :id, :name, :multiple => true, :label => false , :input_html => { :class => 'form-control' } 

now changes saving. it's displaying list_ids not list_names , can't set multiselect options input.

schema db:

create_table "mailing_lists", force: :cascade |t| t.string   "name" t.datetime "created_at", null: false t.datetime "updated_at", null: false 

end

create_table "users", force: :cascade |t| t.string   "email",                  default: "",    null: false t.string   "encrypted_password",     default: "",    null: false t.string   "reset_password_token" t.datetime "reset_password_sent_at" t.datetime "remember_created_at" t.integer  "sign_in_count",          default: 0,     null: false t.datetime "current_sign_in_at" t.datetime "last_sign_in_at" t.string   "current_sign_in_ip" t.string   "last_sign_in_ip" t.datetime "created_at",                             null: false t.datetime "updated_at",                             null: false t.boolean  "admin",                  default: false t.string   "first_name" t.string   "last_name" t.string   "address" t.float    "latitude" t.float    "longitude" t.integer  "mailing_list_id" 

end

class mailinglist has_many : users class user belongs_to :mailing_list 

do need create join table?

i'm learning ruby , ruby on rails zero, accept every criticism :)

thanks