Retire inactive committers

Change-Id: I7ab7cf50370e963c2e5b88b79343a717ea3462b1
Signed-off-by: Daniel Strueber <strueber@mathematik.uni-marburg.de>
diff --git a/contributors.php b/contributors.php
index cdd9fa2..e111ab1 100644
--- a/contributors.php
+++ b/contributors.php
@@ -34,10 +34,7 @@
 <br />
 <p><strong>Active committers</strong>
 <ul>
-<li><a href="https://www.uni-marburg.de/fb12/arbeitsgruppen/swt/kristopher-born">Kristopher Born</a></li>
-<li><a href="http://www.frankhermann.eu/">Frank Hermann</a></li>
 <li><a href="https://www.informatik.hu-berlin.de/de/org/mitarbeiter/1689904">Timo Kehrer</a></li>
-<li><a href="http://www.ckrause.org">Christian Krause</a></li>
 <li><a href="https://rubyfi.de/">Stefan Schulz</a></li>
 <li><a href="https://www.danielstrueber.de">Daniel Str&uuml;ber</a> (project lead)</li>
 <li><a href="https://www.uni-ulm.de/in/pm/mitarbeiter/tichy.html">Matthias Tichy</a></li>
@@ -47,6 +44,9 @@
 <p><strong>Past committers</strong>
 <ul>
 <li>Gregor Bonifer</li>
+<li><a href="https://www.uni-marburg.de/fb12/arbeitsgruppen/swt/kristopher-born">Kristopher Born</a></li>
+<li><a href="http://www.frankhermann.eu/">Frank Hermann</a></li>
+<li><a href="http://www.ckrause.org">Christian Krause</a></li>
 <li>Stefan Jurack</a> (<a href="https://eclipse.org/projects/committers-emeritus.php">committer emeritus</a>)</li>
 <li>Felix Rieger</li>
 <ul>