* `name`: The name of the group. (https://github.com/sakaiproject/Hilary/pull/284 changes this to `displayName`)
* `alias`: The value that the user entered that should be part of the url
* `groupId`: The resource ID for this group.

Say I want to create the group 'My fancy group' that should be approachable at /group/fancy I would end up with:
 * name: 'My fancy group'
 * alias: 'fancy'
 * groupId: 'g:cam:fancy'

Both the name and alias are required in the UI form, so I think the backend should check it as well?