Doctree link dead in readme

[StephenHodgson]

Tried to navigate to link in readme for doctree but link was invalid

[emidoots]

Thanks for taking a look :) The website isn't up yet, I'm still working on it (we're only like a week into development!)

If you're super eager to try it out, there are some Docker commands you can try here: https://github.com/sourcegraph/doctree#try-it-out-extremely-early-stages

[emidoots]

Closing in favor of #8