<div class="container">
  <div class="row col s12">
    <%= form_for @topic do |f|  %>
      <div class="row">
        <div class="input-field col s6">
          <i class="small material-icons">comment</i>
 
  		<%= f.text_field :title %><br />

  		<%= f.text_area :description %><br />

  		<%= f.submit "Update" %>
        </div>
      </div>
	<% end %>
  </div>
</div>

<div class="container">
  <div class="row col s12">
    <%= form_for @topic do |f|  %>
      <div class="row">
        <div class="input-field col s6">
          <i class="small material-icons">comment</i>
 
  		<%= f.text_field :title %><br />

  		<%= f.text_area :description %><br />

  		<%= f.submit "Update" %>
        </div>
      </div>
	<% end %>

  <%= button_to "Delete Topic", topic_path(@topic), :method => :delete %>
  </div>
</div>

Add delete button to edit view
Add delete button to edit view
