Add foreign keys to database

Changing the referrer value for the root admin from 0 to NULL to make
the foreign key check work.

Signed-off-by: Florian Pritz <bluewind@xinu.at>

1 files changed, 1 insertions, 1 deletions

diff --git a/application/controllers/user.php b/application/controllers/user.php
index 7ebaa0b68..b4e2613ac 100644
--- a/application/controllers/user.php
+++ b/application/controllers/user.php
@@ -331,7 +331,7 @@ class User extends MY_Controller {
 		$admininfo = $this->db->query("
 			SELECT email
 			FROM users
-			WHERE referrer = 0
+			WHERE referrer is null
 			ORDER BY id asc
 			LIMIT 1
 			")->row_array();