Added default value 0 for TotalAttempts and CompleteCount

Signed-off-by: Shivam Dixit <shivamd001@gmail.com>
Added controller for adding challenges via AJAX

Signed-off-by: Shivam Dixit <shivamd001@gmail.com>
Added challenge addition in contest dashboard

Signed-off-by: Shivam Dixit <shivamd001@gmail.com>
Fix for #37

Signed-off-by: Shivam Dixit <shivamd001@gmail.com>