Add support for Heroku Redis

[mattstibbs]

Added support for Heroku Redis which sets an environment variable of REDIS_URL.

Not sure if I've missed some implication of simply adding like this but worth a pull request!

[singingwolfboy]

This looks good to me! Can you actually put the Heroku Redis section before Redis To Go? I think it makes more sense that way.

[mattstibbs]

@singingwolfboy Thanks - have swapped those sections around now.

Is it ok that for someone using both Heroku Redis and Redis To Go, Redis To Go would take precedence? Not that I can think of a different way of handling someone using both add-ons at the same time :)

[singingwolfboy]

Actually, because you're using .setdefault(), the first section will take preference, not the last. That's one of the reasons I suggested you switch them. 😄

[singingwolfboy]

Please remove trailing whitespace from this line.

[mattstibbs]

@singingwolfboy Thanks - whitespace removed (and I'll watch out for that in future)

[singingwolfboy]

@mattstibbs You missed a line :)

[mattstibbs]

@singingwolfboy Ah damn. Think I've got it now? (thanks for being patient!)

[singingwolfboy]

Looks great! I'll merge this now. I'll wait a few days to see if @brainix is going to submit another PR (as he said he would in #27). Then, I'll cut a new release and push it to PyPI.

[brainix]

I apologize but I haven't had a chance to get to my PR yet. I'm still going to create a new PR - and I'll do it ASAP, as I know that the release is waiting! Thanks.

[singingwolfboy]

@brainix: no worries, I know how life can get in the way. 😄 There's no hurry. If I don't get a PR from you in a few days, I'll cut a release without it, but we can always make another release after your PR gets in.

[brainix]

Thanks for understanding!