Include a list of features and more screenshots in the README

[dsoprea]

The project has a very cushy rating, but it doesn't seem like there's anywhere I can go to see the list of features. There's a wiki and FAQ, but there's really nothing there other than a cautionary warning about the check-in feature being very broken.

Could use some help.

[Fironet]

The details used to be hosted on a full website called Church.io (example) however that domain now redirects to a Gist list of various church related programs. Couldn't find what occurred in that regard.