How to make users with administrator role member of all organic groups? Is there a way to make all administrator users a member of all the Organic Groups?

For the moment, if an administrator creates an organic group, the only one who will be member of the newly created group will be this particular Admin user.

Maybe I should just find a way to do it throught a Rule ?

UPDATE 
I FOUND HOW:
I found How,

go to your content type and change the widget for your field "og_group_ref" from OG_Reference to Select List