document use with alternatives

[nixjdm]

We should document how to use this plugin with alternatives.

See as an example

https://github.com/pybee/pybee.github.io/blob/lektor/configs/atom.ini

https://github.com/pybee/pybee.github.io/blob/lektor/templates/blog.html#L8

[goanpeca]

I will add the section to the readme

[webknjaz]

Did this ever get implemented in master? I see there's eigengrau@ad6502f in a fork but it seems like lektor-atom still doesn't support alternatives...

[webknjaz]

Aha! So the PR is #16. That looks stale...