app/views/estimations/index.html.erb
<div class="col-lg-6 offest-lg-3 col-md-8 offset-md-2">
<div class="list-group" data-no-turbolink id="estimations-index">
<%= render @estimations %>
</div>
<%= form_for Estimation.new, html: {class: 'form-inline'} do |f| %>
<div class="input-group">
<%= f.text_field :title, class: 'form-control', placeholder: 'New list title' %>
<div class="input-group-append">
<%= f.submit 'Create estimation', class: 'btn btn-success' %>
</div>
</div>
<% end %>
</div>