Note using recommended gitignore

[fulldecent]

GitHub publishes a recommended gitignore for NodeJS projects at https://github.com/github/gitignore/blob/master/Node.gitignore

That approach is not used here. Which is fine.

Please reference the best practice used for departing from the above gitignore, preferably at the top of the gitignore here.

[damccorm]

Added #40 to address this - thanks for the feedback!