Ruby on Rails

to_a' I've got all the combinations (A->B and B->A) and seeded the LanguagePair model. For the cost I was thinking to puts a decimal column in the LanguagePair model.
At the moment I am working on the form(inside the lineitem views):

<div class="field">
      <%= label_tag :from, "Source Language" %><br />
    <%= select_tag :from, options_for_select(@from_lang), {id: 'source_select'} %>
  </div>
  <div class="field">
      <%= label_tag :to, "Target Language" %><br />
    <%= select_tag :to, options_for_select(@to_lang), {id: 'target_select'} %>
  </div>

and LineItem controller:

def new
    @line_item = LineItem.new
    @from_lang = Product.uniq.pluck(:from)
    @to_lang = Product.where(from: @from_lang.first).pluck(:to)
  end


I haven't got a lots of experience with Rails and I am always searching for a better ways to write things.

Regards