diff --git a/docs/sources/installation/ubuntulinux.rst b/docs/sources/installation/ubuntulinux.rst
index 1fb1ce5299..5ccbd59c29 100644
--- a/docs/sources/installation/ubuntulinux.rst
+++ b/docs/sources/installation/ubuntulinux.rst
@@ -92,6 +92,17 @@ have AUFS filesystem support enabled, so we need to install it.
    sudo apt-get update
    sudo apt-get install linux-image-extra-`uname -r`
 
+**add-apt-repository support**
+
+Some installations of Ubuntu 13.04 (Digital Ocean's Ubuntu 13.04 x64 Server in
+this case) require software-properties-common to be installed before being able
+to use add-apt-repository.
+
+.. code-block:: bash
+
+  sudo apt-get install software-properties-common
+
+
 Installation
 ------------