Move GitHub ribbon to the right (#67)

* Move GitHub ribbon to the right

We currently have many extensions and profiles and the ribbon gets 
in the way. As it's not possible to scroll the left panel, it's
hard to click on an extension.

* Changes from CR

priv/static/css/app.css

@@ -136,12 +136,12 @@ body {
   }
 
   .github-ribbon {
-    position: absolute;
+    position: fixed;
     width: 150px;
     height: 150px;
     overflow: hidden;
     z-index: 1;
-    left: 0px;
+    right: 0px;
     bottom: 0px;
   }
   .github-ribbon a {
@@ -150,15 +150,15 @@ body {
     overflow: hidden;
     padding: 6px 0px;
     text-align: center;
-    transform: rotate(45deg);
+    transform: rotate(-45deg);
     text-decoration: none;
     color: rgb(255, 255, 255);
     position: inherit;
     box-shadow: rgba(0, 0, 0, 0.5) 0px 2px 3px 0px;
     background-color: rgb(160, 0, 0);
-    left: -40px;
+    right: -40px;
     background-image: linear-gradient(rgba(0, 0, 0, 0), rgba(0, 0, 0, 0.5));
-    bottom: 45px;
+    bottom: 60px;
   }
 }
 
@@ -241,6 +241,7 @@ li {
 
 /* Custom page footer */
 .footer {
+  z-index: 2;
   position: fixed;
   bottom: 0;
   width: 100%;