Fix docuomentation link in README.md (#496)

Current value 404s since the docs website is not a repo, but rather github pages served out of github.io

Same fix needs to be made in the repo's metadata - thought I suspect that's a UI-based, not code-based, fix.

Author: manuelgomes

README.md

@@ -324,5 +324,5 @@ Use the GitHub [issue tracker][ice_cube-issues]
 [travis-ice_cube-badge_image]: https://secure.travis-ci.org/seejohnrun/ice_cube.svg
 [ice_cube-lone_star_pdf]: http://seejohnrun.github.com/ice_cube/static/lsrc_ice_cube.pdf
 [ice_cube-ruby_nyc_pdf]: http://seejohnrun.github.com/ice_cube/static/ice_cube_ruby_nyc.pdf
-[ice_cube-docs]: http://seejohnrun.github.com/ice_cube/
+[ice_cube-docs]: http://seejohnrun.github.io/ice_cube/
 [ice_cube-issues]: https://github.com/seejohnrun/ice_cube/issues