Don't allow to create more than one child campaign per user

app/controllers/campaigns_controller.rb

@@ -111,6 +111,10 @@ class CampaignsController < ApplicationController
     session[:donor_signup_url] = request.env["REQUEST_URI"]
     @nonprofit = Nonprofit.find_by_id(params[:npo_id])
     @parent_campaign = Campaign.find_by_id(params[:campaign_id])
+    @child_campaign = Campaign.where(
+      profile_id: current_user.profile.id,
+      parent_campaign_id: @parent_campaign.id
+    ).first if @parent_campaign
     @profile = current_user.profile if current_user
   end
 

app/views/campaigns/peer_to_peer.html.erb

@@ -116,6 +116,7 @@
       </li>
 
       <li>
+        <% if !@child_campaign %>
           <p class='strong u-marginBottom--15'>Start your campaign</p>
           <span class='annot'>5 minutes</span>
           <div class='u-paddingLeft--20 u-maxWidth--500'>
@@ -138,7 +139,13 @@
               </button>
             </div>
           </div>
+        <% else %>
+          <p>
+            Seems like you already have a campaign for that cause! <%= link_to "Click here to see it", @child_campaign.url %>.
+          </p>
+        <% end %>
       </li>
+
     </ul>
   </div>
 </main>