minor #82 Bootstrapping property info doc (weaverryan)

This PR was squashed before being merged into the 2.8 branch (closes #82).

Discussion
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Bootstrapping property info doc

Commits
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eec1e2f Bootstrapping property info doc

Author: javiereguiluz

components/property_info.rst

@@ -0,0 +1,22 @@
+.. index::
+   single: PropertyInfo
+   single: Components; PropertyInfo
+
+The PropertyInfo Component
+==========================
+
+    The PropertyInfo component extracts information about PHP class properties using
+    metadata from popular sources, like Reflection and PHP Documentation.
+
+.. versionadded:: 2.8
+    The PropertyInfo component was introduced in Symfony 2.8.
+
+Installation
+------------
+
+You can install the component in 2 different ways:
+
+* :doc:`Install it via Composer </components/using_components>` (``symfony/property-info`` on `Packagist`_);
+* Use the official Git repository (https://github.com/symfony/property-info).
+
+For more information, see the code in the Git Repository.