rearrange sponsors according to tiers

Author: Franziska Schmidt

index.html

@@ -335,15 +335,19 @@ <h2>Sponsors October 2017</h2>
         <a href="https://www.circleci.com/" title="CircleCI">
          <img class="supporter-logo" src="/images/logos/circleci.png">
        </a>
+       <a href="https://nextjournal.com/" title="Nextjournal">
+          <img class="supporter-logo" src="/images/logos/nextjournal.svg">
+        </a>
        <a href="https://www.cognitect.com/" title="Cognitect">
          <img class="supporter-logo" src="/images/logos/cognitect.jpg">
        </a>
-       <a href="https://www.mapbox.com/" title="Mapbox">
-         <img class="supporter-logo" src="/images/logos/mapbox.png">
-       </a>
+      </div>
      </div>
      <div class="row supporter-area">
       <div class="col-md-12 supporter-logos">
+       <a href="https://www.mapbox.com/" title="Mapbox">
+         <img class="supporter-logo" src="/images/logos/mapbox.png">
+       </a>
        <a href="https://lambdaisland.com" title="Lambda Island">
          <img class="supporter-logo" src="/images/logos/lambdaisland.png">
        </a>
@@ -353,11 +357,7 @@ <h2>Sponsors October 2017</h2>
        <a href="https://www.microsoft.com/" title="Microsoft">
          <img class="supporter-logo" src="/images/logos/microsoft.png">
        </a>
-       <a href="https://nextjournal.com/" title="Nextjournal">
-          <img class="supporter-logo" src="/images/logos/nextjournal.svg">
-        </a>
-      </div>
-    </div>
+   </div>
     <div class="col-md-offset-4 col-md-4">
         <a href="https://clojurebridge-berlin.github.io/sponsor-us">
           <button type="button" class="btn btn-success">Sponsor us!</button>