Write the complete documentation.

[Malstrom]

How to install, for example... like all others gems. )))

[ltfschoen]

@Malstrom I just finished setting up ActsAsTree Gem v2.7 on this Peerism project. I've thoroughly explained how I set it up in the README since it took me quite a long time.
If anyone can think of any ways I may improve the code, please let me know. I'd really appreciate it.