Add ReadMe file

Based on original instructions from site wiki per #117:
https://github.com/dita-ot/dita-ot.github.io/wiki/Building-site-output

Signed-off-by: Roger Sheen <roger@infotexture.net>

README.md

@@ -0,0 +1,140 @@
+# dita-ot.github.io
+
+This repository contains the source files for the **DITA Open Toolkit** project website at [dita-ot.org][1].
+
+For details and background information on how we build and maintain the site, visit [dita-ot.org/colophon][2].
+
+---
+
+If you'd like to set up a local staging environment and build a copy of the site, follow the instructions below.
+
+<!-- MarkdownTOC autolink="true" bracket="round" levels="2" -->
+
+- [Environment setup](#environment-setup)
+- [Install prerequisite software](#install-prerequisite-software)
+- [Building site output](#building-site-output)
+- [Updating JavaScript](#updating-javascript)
+- [Happy staging!](#happy-staging)
+
+<!-- /MarkdownTOC -->
+
+## Environment setup
+
+1.  Clone the DITA-OT and project website repositories:
+
+        git clone https://github.com/dita-ot/dita-ot.git
+        git clone https://github.com/dita-ot/dita-ot.github.io.git
+
+    **NOTE:** The examples below assume the the DITA-OT and project website repositories have been cloned to a common parent directory, such as your home folder. If you clone the repositories to a different location, substitute that path for the tilde symbol `~` in the samples below.
+
+2.  Move to the DITA-OT directory:
+
+        cd dita-ot
+
+3.  Fetch the submodules:
+
+        git submodule update --init --recursive
+
+4.  In the root directory, run the Gradle wrapper to compile the Java code and install plugins:
+
+        ./gradlew
+
+5.  Install the HTML plug-in for the DITA-OT project website: `org.dita-ot.html`
+
+        src/main/bin/dita --install https://github.com/dita-ot/org.dita-ot.html/archive/master.zip
+
+## Install prerequisite software
+
+1.  Install [Jekyll][3]:
+
+        gem install jekyll
+
+2.  Install [Bundler][4]:
+
+        gem install bundler
+
+3.  Switch to your clone of the project website repository:
+
+        cd ~/dita\-ot\.github\.io
+
+4.  Install all of the required gems from the project’s `Gemfile`:
+
+        bundle install
+
+5.  Run Jekyll.
+
+        bundle exec jekyll serve
+
+    This runs the production version of the site locally, so you can view your local clone of the project website at [http://127.0.0.1:4000/][5].
+
+    At this stage, what you see there should be identical to the production version of the project website at [www.dita-ot.org][1].
+
+    **Note:** For more details, see [Setting up your GitHub Pages site locally with Jekyll][6].
+
+## Building site output
+
+1.  Switch to the `docsrc` submodule of the local `dita-ot` clone:
+
+        cd ~/dita-ot/src/main/docsrc
+
+2.  Check out the `develop` branch of the `docs` repository to update the `docsrc` submodule pointer to the latest development state _(or to another branch if you need to generate output for that)_:
+
+        git checkout develop
+
+3.  Run the `site` build task with the Gradle wrapper to generate the output for the project website:
+
+        ./gradlew site
+
+The output will be generated by default in `src/main/docsrc/build/site`.
+
+_(This appears as unstyled HTML when viewed in place.)_
+
+To redirect the output to the `dev` development folder that Jekyll serves, pass the `outputDir` parameter to the build script as follows:
+
+    ./gradlew site -PoutputDir=~/dita-ot.github.io/dev
+
+After the build completes, you should find the results in the **Docs \> Development** section of the local staging environment [http://127.0.0.1:4000/dev/][7].
+
+To automatically regenerate the site output whenever documentation source files change, add the `--continuous` build option:
+
+    ./gradlew site -PoutputDir=~/dita-ot.github.io/dev --continuous
+
+## Updating JavaScript
+
+If you need to change any of the JavaScript files in the site repository, you'll need to [download & install Node.js][8] and run the `npm` package manager for JavaScript to install the project dependencies:
+
+    npm ci
+
+This will install various Node modules including [Gulp][9], the streaming build system.
+
+To run Gulp separately, you may need to install it per <https://gulpjs.com>:
+
+    npm install gulp-cli -g
+    npm install gulp -D
+
+To make changes to the JavaScript code, add or edit source files in the `_js` folder.
+
+You can then run Gulp to minify the modified JavaScript code:
+
+    gulp
+
+Or run the `watch-js` task to monitor the JavaScript source files in the `_js` folder for changes, and compile the minified code to the `js` folder whenever the source files change:
+
+    gulp watch-js
+
+## Happy staging!
+
+You can now use the local staging environment to test your changes before committing your work.
+
+When you're ready to share your progress, send us a [pull request][10].
+
+[1]: https://www.dita-ot.org
+[2]: https://www.dita-ot.org/colophon
+[3]: https://jekyllrb.com
+[4]: https://bundler.io
+[5]: http://127.0.0.1:4000/
+[6]: https://help.github.com/articles/setting-up-your-github-pages-site-locally-with-jekyll/
+[7]: http://127.0.0.1:4000/dev/
+[8]: https://nodejs.org/en/download/
+[9]: https://gulpjs.com
+[10]: https://help.github.com/articles/about-pull-requests/

_config.yml

@@ -28,6 +28,7 @@ exclude:
   - LICENSE
   - node_modules
   - package*.js*
+  - README.md
 
 # Enable redirects (#43)
 plugins: