mirroring support...

conf/example.gitolite.rc
  - "slave mode" flag to disable pushes and "list of slaves"

hooks/common/post-receive.mirrorpush
  - code to push to the mirror, creating the repo if needed

src/mirror-shell
  - shell for master pushing to a slave, because we don't actually want
    to go through gitolite itself, yet we have to take care of
    $REPO_BASE being wherever.  And of course we have to set
    GL_BYPASS_UPDATE_HOOK to 1 for the push to happen!

src/gl-mirror-sync
  - manually runnable program to sync from current server to another

hooks/common/post-receive.mirrorpush

@@ -0,0 +1,21 @@
+#!/bin/bash
+
+# gitolite mirroring
+
+# please see doc/mirroring.mkd for instructions on how to use this
+
+if [ -n "$GL_SLAVES" ]
+then
+    for mirror in $GL_SLAVES
+    do
+        if git push --mirror $mirror:$GL_REPO.git
+        then
+            :
+        else
+            ssh $mirror mkdir -p $GL_REPO.git
+            ssh $mirror git init --bare $GL_REPO.git
+            git push --mirror $mirror:$GL_REPO.git ||
+                echo "WARNING: mirror push to $mirror failed"
+        fi
+    done
+fi >&2