app/views/conversations/show.html.erb
<p id="notice"><%= notice %></p>
<div class="row col-md-8 col-md-offset-2">
<div class="panel panel-default">
<% if @conversation.messages.any? %>
<div class="panel-body" id="messages">
<%= render partial: 'messages/message', collection: @messages %>
</div>
<%else%>
<div class="panel-body hidden" id="messages">
</div>
<%end%>
</div>
<%= render partial: 'messages/message_form', locals: { message: @message, conversation: @conversation }%>
</div>
<%= link_to 'Back', conversations_path %>