[IMP] upgrade: create new "upgrade" section in "install and maintain"

closes odoo#1187

X-original-commit: fd006b4
Signed-off-by: Antoine Vandevenne (anv) <[email protected]>
Signed-off-by: Jonathan <[email protected]>

Author: jcs-odoo

content/administration.rst

@@ -18,4 +18,5 @@ These guides provide instructions on how to install, maintain and upgrade Odoo d
 
     administration/install
     administration/maintain
+    administration/upgrade
     administration/odoo_sh

content/administration/maintain.rst

@@ -7,7 +7,6 @@ Maintain
 .. toctree::
 
     maintain/update
-    maintain/db_upgrade
     maintain/enterprise
     maintain/hosting_changes
     maintain/on_premise