app/views/shared/_error_messages.html.erb
<% if target.errors.any? %>
<div class="panel panel-error error-message">
<span class="geomicon geomicon-alert"></span>
<div class="panel-title"><%= t('.oops_went_wrong') %></div>
<div class="panel-body">
<ul>
<% target.errors.full_messages.each do |message| %>
<li>
<%= message %>
</li>
<% end %>
</ul>
</div>
</div>
<% end %>