Feature Request: Restrict access per environment

[jonrosner]

Currently, only entire collections can be access restricted via groups. It would be nice if environments could be access restricted, too.

The logic should be:

• any user that's part of any group of the collection can see the collection (already exists)
• if an environment has no group set, any user that can see the collection can see the environment. If an environment has 1 or more groups set, any user that's part of any group of the environment can see the environment

This logic will allow backward compatibility.