Update installation.rst

Refer to PGP signature verification in the installation instructions for tarballs.

diff --git a/doc/installation.rst b/doc/installation.rst
index d402f8a..8e9c9be 100644 (file)
--- a/doc/installation.rst
+++ b/doc/installation.rst
@@ -39,8 +39,9 @@ Installing from the tarball release
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 1. Download the most recent tarball from the `download page`_
-2. Unpack the tarball
-3. Move the files somewhere in your project
+2. Verify the integrity of the tarball http://fabien.potencier.org/article/73/signing-project-releases
+3. Unpack the tarball
+4. Move the files somewhere in your project
 
 Installing the development version
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~