Add Jekyll tag to isolate "production-only" doc components.

Author: Patrick Wendell <pwendell@gmail.com>

Closes #56 from pwendell/jekyll-prod and squashes the following commits:

1bdc3a8 [Patrick Wendell] Add Jekyll tag to isolate "production-only" doc components.

1 files changed, 16 insertions, 3 deletions

diff --git a/docs/README.md b/docs/README.md
index cac65d97e4..0678fc5c86 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -10,9 +10,22 @@ We include the Spark documentation as part of the source (as opposed to using a
 
 In this directory you will find textfiles formatted using Markdown, with an ".md" suffix. You can read those text files directly if you want. Start with index.md.
 
-To make things quite a bit prettier and make the links easier to follow, generate the html version of the documentation based on the src directory by running `jekyll build` in the docs directory. Use the command `SKIP_SCALADOC=1 jekyll build` to skip building and copying over the scaladoc which can be timely. To use the `jekyll` command, you will need to have Jekyll installed, the easiest way to do this is via a Ruby Gem, see the [jekyll installation instructions](http://jekyllrb.com/docs/installation). This will create a directory called _site containing index.html as well as the rest of the compiled files. Read more about Jekyll at https://github.com/mojombo/jekyll/wiki.
-
-In addition to generating the site as html from the markdown files, jekyll can serve up the site via a webserver. To build and run a local webserver use the command `jekyll serve` (or the faster variant `SKIP_SCALADOC=1 jekyll serve`), which runs the webserver on port 4000, then visit the site at http://localhost:4000.
+The markdown code can be compiled to HTML using the 
+[Jekyll tool](http://jekyllrb.com).
+To use the `jekyll` command, you will need to have Jekyll installed. 
+The easiest way to do this is via a Ruby Gem, see the 
+[jekyll installation instructions](http://jekyllrb.com/docs/installation). 
+Compiling the site with Jekyll will create a directory called 
+_site containing index.html as well as the rest of the compiled files.
+
+You can modify the default Jekyll build as follows:
+
+    # Skip generating API docs (which takes a while)
+    $ SKIP_SCALADOC=1 jekyll build
+    # Serve content locally on port 4000
+    $ jekyll serve --watch
+    # Build the site with extra features used on the live page
+    $ PRODUCTION=1 jekyll build
 
 ## Pygments