How to allow any user to create issues in a public project?

I have a public project that I have setup for users that are requesting access to another project. How would I allow any registered user to create a ticket in this project, even if they aren't apart of that project?

It seems like the actual redmine site is setup like that. I am not a member of the Redmine project, but I can create a new issue all the same.

I might be missing a setting somewhere, but I just can't find it.