[DOCS] Added initial documentation

This commit adds preliminary documentation for the Aluminum project. /docs/index.rst summarizes the purpose of the Aluminum project and some of its key features. It will be served at the documentation homepage:
aluminumjs.rtfd.io

docs/index.rst

@@ -3,18 +3,31 @@
    You can adapt this file completely to your liking, but it should at least
    contain the root `toctree` directive.
 
-Welcome to Aluminum's documentation!
-====================================
+**************
+About Aluminum
+**************
 
-.. toctree::
-   :maxdepth: 2
-   :caption: Contents:
+What is Aluminum?
+=================
+
+Aluminum is a lightweight web server written entirely in `Node.js <https://www.nodejs.org>`_, "an asynchronous event-driven JavaScript runtime ... designed to build scalable network applications." It includes not only a traditional static file server, but also various other features that simplify the web development process, such as an authentication server and a network-based cryptography server.
+
+Why Aluminum?
+-------------
 
+Aluminum is simple to install and easy to use. Simply clone the git repository, install the dependencies automatically with ``yarn``, and copy the default configuration files into the higher level directory. Starting the web server is as simple as typing ``yarn run start`` into your terminal.
 
+.. seealso:: See the installation guide for a detailed tutorial on getting started with Aluminum.
 
-Indices and tables
-==================
+It also offers several unique and useful features:
 
-* :ref:`genindex`
-* :ref:`modindex`
-* :ref:`search`
+* **Highly Customizable:** Use an official extension, a community-contributed one, or make your own.
+* **Integrated Authentication Server:** Verify end users' identity without leaving the Aluminum platform.
+* **PHP support:** If you're uncomfortable using Node.js for server-side scripting, Aluminum is also compatible with PHP.
+* **And more:** Math rendering, network based time synchronization, simplified cryptography, etc.
+
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Contents:
+   :numbered: