Some fixes to participation controls

* prevent default event in JS handlers to prevent jumping back to the
  top.
* Use js-routes
* Use sprite for icons
* Reply with 200 instead of 204 when destroying a participation,
  to prevent errors in the browser console.

app/assets/javascripts/app/views/stream_post_views.js

@@ -117,16 +117,18 @@ app.views.StreamPost = app.views.Post.extend({
   },
 
   createParticipation: function (evt) {
+    if(evt) { evt.preventDefault(); }
     that = this;
-    $.post("/posts/" + this.model.get("id") + "/participation", {}, function () {
+    $.post(Routes.post_participation_path(this.model.get("id")), {}, function () {
       that.model.set({participation: true});
       that.render();
     });
   },
 
   destroyParticipation: function (evt) {
+    if(evt) { evt.preventDefault(); }
     that = this;
-    $.post("/posts/" + this.model.get("id") + "/participation", { _method: "delete" }, function () {
+    $.post(Routes.post_participation_path(this.model.get("id")), { _method: "delete" }, function () {
       that.model.set({participation: false});
       that.render();
     });

app/assets/stylesheets/application.css.scss

@@ -281,20 +281,18 @@ ul.as-selections {
   }
   .create_participation {
     display: inline-block;
-    .icons-create-participation {
+    .icons-create_participation {
       height: 14px;
       width: 14px;
-      background: image-url("icons/create_participation.png") center;
     }
   }
   .destroy_participation {
     display: inline-block;
-    .icons-destroy-participation {
+    .icons-destroy_participation {
       height: 14px;
       width: 14px;
-      background: image-url("icons/destroy_participation.png") center;
     }
-  }  
+  }
   .delete {
     display: inline-block;
     .icons-deletelabel {

app/assets/templates/stream-element_tpl.jst.hbs

@@ -18,13 +18,13 @@
           </a>
           {{#if participation}}
             <a href="#" rel="nofollow" class="destroy_participation" title="{{t "stream.disable_post_notifications"}}">
-              <div class="icons-destroy-participation control_icon"></div>
+              <div class="icons-destroy_participation control_icon"></div>
             </a>
           {{else}}
             <a href="#" rel="nofollow" class="create_participation" title="{{t "stream.enable_post_notifications"}}">
-              <div class="icons-create-participation control_icon"></div>
+              <div class="icons-create_participation control_icon"></div>
             </a>
-          {{/if}}     
+          {{/if}}
           <a href="#" rel="nofollow" class="delete hide_post" title="{{t "stream.hide"}}">
             <div class="icons-deletelabel delete control_icon"/>
           </a>
@@ -35,7 +35,7 @@
         {{/unless}}
       </div>
     {{/if}}
-    
+
     <div>
       {{#with author}}
         <a href="/people/{{guid}}" class="author {{{hovercardable this}}}">{{name}}</a>

app/controllers/participations_controller.rb

@@ -5,19 +5,19 @@ class ParticipationsController < ApplicationController
     post = current_user.find_visible_shareable_by_id(Post, params[:post_id])
     if post
       current_user.participate! post
-      render :nothing => true, :status => :created
+      render nothing: true, status: :created
     else
-      render :nothing => true, :status => :forbidden
+      render nothing: true, status: :forbidden
     end
   end
 
   def destroy
-    @participation = current_user.participations.find_by :target_id => params[:post_id]
-    if @participation
-      @participation.destroy
-      render :nothing => true, :status => :no_content
+    participation = current_user.participations.find_by target_id: params[:post_id]
+    if participation
+      participation.destroy
+      render nothing: true, status: :ok
     else
-      render :nothing => true, :status => :unprocessable_entity
+      render nothing: true, status: :unprocessable_entity
     end
   end
 end