Add a command to create README

[alysbrooks]

Various project templates (for Clojure and beyond) include README templates. It would be handy to have a command to create one conveniently.

Original message (which upon rereading, is a little confusing):

I've been thinking it might be helpful. On the one hand, it's pretty easy to create a new file named README . On the other hand, reducing the friction as much as possible might encourage people to write more documentation 🙂 (I'm planning to do a talk on documentation, so I've been brainstorming ways to make the barrier to entry as low as possible.)