New Category
<%= form_for(@category, html: { class: 'square' }) do |f| %>
<%= render 'shared/errors', messages: @category.errors.full_messages %>
<%= f.label :name %>
<%= f.text_field :name %>
<%= f.label :domain %>
<%= f.select :domain, @category.domains.invert %>
<%= f.submit 'Create Category' %>
<% end %>