Need to figure out why this is still happening that `relative_url` is
not prepending the right value at just random times.

Trying to remove baseurl term.

Key change is using the new `absolute_url` and `relative_url` filters

http://jekyllrb.com/news/2016/10/06/jekyll-3-3-is-here/
https://github.com/blog/2277-what-s-new-in-github-pages-with-jekyll-3-3

rocksdb hit the problem that nuclide had.

https://github.com/facebook/nuclide/issues/789
https://github.com/facebook/nuclide/pull/793

Summary:
This adds the actual RocksDB Google Analytics ID that will be used when
we switch over from WP to GH-pages

Test Plan: visual

Reviewers: IslamAbdelRahman, lgalanis, sdong

Reviewed By: sdong

Subscribers: sdong, andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D63429

Summary:
The new blog post links will be formatted differently coming over to gh-pages. But
we can redirect from the old style over to the new style for existing blog posts.

Test Plan:
Visual

https://www.facebook.com/pxlcld/pvWQ

Reviewers: lgalanis, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D63513

Summary:
This is the proof of concept for the initial landing page for RocksDB when we move to GitHub pages.

The images for each feature can change, but using these as placeholders for now.

The styling may change a bit as well.

Test Plan: Visual

Reviewers: IslamAbdelRahman, lgalanis, sdong

Reviewed By: lgalanis

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D62985

This is the initial commit with the templates necessary to have our RocksDB user documentation hosted on GitHub pages.

Ensure you meet requirements here: https://help.github.com/articles/setting-up-your-github-pages-site-locally-with-jekyll/#requirements

Then you can run this right now by doing the following:

```
% bundle install
% bundle exec jekyll serve --config=_config.yml,_config_local_dev.yml
```

Then go to: http://127.0.0.1:4000/

Obviously, this is just the skeleton. Moving forward we will do these things in separate pull requests:

- Replace logos with RocksDB logos
- Update the color schemes
- Add current information on rocksdb.org to markdown in this infra
- Migrate current Wodpress blog to Jekyll and Disqus comments
- Etc.