developer-manual: Mention that merges into 'master' should be avoided

diff --git a/doc/source/developer-manual.sgml b/doc/source/developer-manual.sgml
index 2c32912..43bf7be 100644 (file)
--- a/doc/source/developer-manual.sgml
+++ b/doc/source/developer-manual.sgml
@@ -188,6 +188,10 @@ Hal.
        such changes are fully tested ought they be pushed back to the central
        repository master branch.
      </para>
+     <para>
+       Before pushing stuff, please rebase it on a current master so we get
+       an uncomplicated commit history. Avoid merges where possible.
+     </para>
      <!--
      <para>
        Branches are used to fork a sub-development path from the main trunk.