How to position submit button on same line as input with Simple Form and Bootstrap?

Question

Using Simple Form and Bootstrap, I would like to have the following appear in-line instead of having the submit button below the input select.

<%= simple_form_for :select_rollout, :html => {:class => "form-inline"}, do |f| %>
  <%= f.input :rollout_id, collection: @rollout_options, :label => false %>
  <%= f.button :submit, "Apply" %>
<% end %>

The following solution only works for inputs (the submit button is rendered outside the div for the inputs):

<%= form.input :city, label: 'City/State/Zip', input_html: {class: 'span3'}, wrapper_html: {class: 'controls controls-row'} do %>
  <%= form.input_field :city, class: 'span1' %>
  <%= form.input_field :state, class: 'span1' %>
<% end %>

Answer 1

To solve this, I needed to use input_field inside an input block, and use the inline-form style on the wrapper for the block:

<%= f.input :rollout_id, :label => false, wrapper_html: {class: "form-inline"} do %>
  <%= f.input_field :rollout_id, collection: @rollout_options, :label => false %>
  <%= f.button :submit, "Apply", :class => "btn-primary" %>
<% end %>

Hope this helps someone.