[fix] welcome mail if no other app

frappe/core/doctype/user/user.py

@@ -265,7 +265,10 @@ class User(Document):
 		link = self.reset_password()
 
 		app_title = [t for t in frappe.get_hooks('app_title') if t != 'Frappe Framework']
-		subject = _("Welcome to {0}").format(app_title[0])
+		if app_title:
+			subject = _("Welcome to {0}").format(app_title[0])
+		else:
+			subject = _("Complete Registration")
 
 		self.send_login_mail(subject, "templates/emails/new_user.html",
 				dict(