While testing IMS OBv2.1 with the certification platform we've faced this issue: current backpacks don't support more then 255 in the URLs.
This restriction should be removed to let users define longer URLs.

Steps to reproduce:

1. Login as admin
2. Go to "Site administration > Badges > Manage backpacks".
3. Create a new backpack with an URL longer than 50 (for instance, https://certification.imsglobal.org/badgewebapi/rest )

Expected behaviour:

Backpack should be created.

Current behaviour:

An error about the 255 characters limitation is displayed.