It's very easy to forget to add `require 'rails_helper'` at the top of every core/plugin spec file, and omissions can cause some very confusing/sporadic errors.
By setting this flag in `.rspec`, we can remove the need for `require 'rails_helper'` entirely.
If a group you're a member of is invited to a PM, you can no longer remove yourself from it. This means you won't be able to remove the message from your inbox, and even if you archive it, it'll come back once someone replies.