Added this file for documentation of maintenance tasks

diff --git a/doc/MAINTENANCE b/doc/MAINTENANCE
new file mode 100755 (executable)
index 0000000..28d5844
--- /dev/null
+++ b/doc/MAINTENANCE
@@ -0,0 +1,5 @@
+To dump mir database <dbname>:
+
+       pg_dump -b -o -F t <dbname> > mir_dump.tar
+
+This genrates a tar file including blobs as data.
\ No newline at end of file