Update readme

Author: derickr

README.rst

@@ -1,12 +1,51 @@
 MongoDB
 =======
 
-This is a proof-of-concept HHVM extension mimicking the proof-of-concept PHP
-extension "phongo".
+This is the low-level HHVM driver for MongoDB. It implements the same
+interface as the PHP driver for MongoDB that you will find at
+https://pecl.php.net/package/mongodb. The documentation for both of them is
+therefore (mostly) the same, and can be found at
+http://docs.php.net/manual/en/set.mongodb.php
+
+The driver is written to be a bare bone layer to talk to MongoDB, and
+therefore misses many convenience features. Instead, these convenience methods
+have been split out into a layer written in PHP, the `MongoDB Library`_.
+Using this library should be your preferred way of interacting with MongoDB.
+
+Please note that the new HHVM and PHP drivers implement a different API from
+the legacy driver at http://pecl.php.net/package/mongo, and hence, you will
+find it hard for other libraries like `Doctrine MongoDB's ODM`_ will not work
+with the new drivers.
+
+.. _`Doctrine MongoDB's ODM`: http://doctrine-mongodb-odm.readthedocs.org/en/latest/
+.. _`MongoDB Library`: http://mongodb-labs.github.io/mongo-php-library-prototype/
 
 Building
 --------
 
+From a package (.tgz)
+~~~~~~~~~~~~~~~~~~~~~
+
+Releases of this driver can be found on
+https://s3.amazonaws.com/drivers.mongodb.org/hhvm/index.html
+
+Please download the latest .tgz file into a directory, and run the following
+commands::
+
+	mkdir hhvm-mongodb
+	cd hhvm-mongodb
+	tar -xvzf ../hhvm-mongodb-1.0alpha1
+	cd hhvm-mongodb-1.0alpha1
+	cd libbson; ./autogen.sh; cd ..
+	cd libmongoc; ./autogen.sh; cd ..
+	hphpize
+	cmake .
+	make -j 16
+	make install
+
+From source
+~~~~~~~~~~~
+
 Compiling this extension requires the ``hphpize`` command, which is available by
 installing the ``hhvm-dev`` package from the
 `HHVM repositories <https://github.com/facebook/hhvm/wiki/Prebuilt-Packages-for-HHVM>`_
@@ -31,10 +70,19 @@ After cloning the repository, the extension may be built like so::
 	make -j 5
 	make install
 
-Running
--------
+Installing
+----------
+
+In your ``/etc/hhvm/php.ini``, add the following lines (adjusting paths if
+necessary)::
+
+	hhvm.dynamic_extension_path=/usr/local/hhvm/3.9.1/lib/hhvm/extensions/20150212
+	hhvm.dynamic_extensions[mongodb]=mongodb.so
+
+Running Tests
+-------------
 
 To run the rests::
 
 	export TEST_PHP_EXECUTABLE=`which hhvm`
-	hhvm -vDynamicExtensions=mongodb.so run-tests.php
+	hhvm -vDynamicExtensions.0=/usr/local/hhvm/3.9.1/lib/hhvm/extensions/20150212/mongodb.so run-tests.php