Rails4에서 PG String Array type 사용하기

class AddInstagramCodesToItem < ActiveRecord::Migration
    def change
        add_column :items, :instagram_codes, :string, array: true
    end
end

<div class="form-group">
    <%= f.label :instagram_codes, "Instagram", class: "col-sm-2 control-label" %>
    <div class="col-sm-10" id="item-price-selection-list">
      <%= f.text_field :instagram_codes, class: "form-control"%>
    </div>
</div>

private

def item_params
    params.require(:item).permit(:instagram_codes, ...)
end

def create
    if @item.save
        @item.update_attribute(:instagram_codes,item_params[:instagram_codes].split(", ").map {|c| c.strip})
        ...
end

def update
    if @item.update_attributes(item_params)
        @item.update_attribute(:instagram_codes,item_params[:instagram_codes].split(", ").map {|c| c.strip})
        ...
end