Add 'Donate' button

wiki/src/donate.css

@@ -8,6 +8,11 @@
   border: solid 3px white;
 }
 
+#donate-button .col-md-12 {
+  margin-top: 1em;
+  border: solid 3px white;
+}
+
 .amounts .btn {
   padding-top: 33px;
   height: 95px;

wiki/src/donate.html

@@ -96,5 +96,9 @@
   </label>
 </div>
 
+<div id="donate-button" class="row">
+  <button class="btn btn-primary btn-lg btn-block col-md-12">Donate</button>
+</div>
+
   </div>
 </div>