Change "reusability" to "type" for invites

- This makes the choice much clearer
- Allows for less generic terms in the table
- Future extensibility \o/

snikket_web/templates/admin_create_invite_form.html

@@ -5,8 +5,8 @@
 	<h2 class="form-title">{% trans %}Create new invitation{% endtrans %}</h2>
 	<p class="form-descr weak">{% trans %}Create a new invitation link to invite more users to your Snikket service by clicking the button below.{% endtrans %}</p>
 	<div class="f-ebox">
-		{{ invite_form.reusable }}
-		{{ invite_form.reusable.label }}
+		{{ invite_form.type_.label }}
+		{{ invite_form.type_ }}
 	</div>
 	<div class="f-ebox">
 		{{ invite_form.lifetime.label }}