Added 'json' to config/mimes.php.
diff --git a/application/config/mimes.php b/application/config/mimes.php
index 58eea5f..8065794 100644
--- a/application/config/mimes.php
+++ b/application/config/mimes.php
@@ -97,7 +97,8 @@
 				'xlsx'	=>	'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
 				'word'	=>	array('application/msword', 'application/octet-stream'),
 				'xl'	=>	'application/excel',
-				'eml'	=>	'message/rfc822'
+				'eml'	=>	'message/rfc822',
+				'json' => array('application/json', 'text/json')
 			);