Add submit button

en/participate.html

@@ -33,7 +33,7 @@
                         href="https://www.ccc.de/hackerethik">ethics</a> and want to help, you are cordially invited.
                 </p>
                 <div class="button-container">
-                    <a href="index.html" class="button">To the main page</a>
+                    <a href="https://cfp.cttue.de/tdf4/locale/set?locale=en&next=/tdf4/cfp" class="button">Submit your contribution</a>                   
                 </div>
             </div>
 

participate.html

@@ -44,7 +44,7 @@
 					dazu
 					eingeladen.</p>
 				<div class="button-container">
-					<a href="index.html" class="button">Zur Hauptseite</a>
+					<a href="https://cfp.cttue.de/tdf4/locale/set?locale=de&next=/tdf4/cfp" class="button">Beitrag einreichen</a>
 				</div>
 			</div>