Add GH Pages infrastructure

Start to migrate from README.md to the Pages infrastructure
for nicer looking and more organized docs.

docs/Gemfile

@@ -0,0 +1,14 @@
+# Bundler setup for jekyll to be deployed on github pages.
+
+source "https://rubygems.org"
+
+# Note that we're using the github-pages gem to mimic the GitHub pages
+# automated setup. That installs jekyll, a default set of jekyll
+# plugins, and a modified jekyll configuration.
+group :jekyll_plugins do
+  gem "github-pages"
+  gem "jekyll-remote-theme"
+end
+
+# Prefer the GitHub flavored markdown version of kramdown.
+gem "kramdown-parser-gfm"