Merge pull request #164 from kevin1/kevin1_add_apt_dependencies

README: Add apt dependencies for pypi cryptography.

README.md

@@ -30,7 +30,7 @@ The easiest way to get an Algo server running is to let it setup a _new_ virtual
 1. Install the dependencies for your operating system:
 
  OS X: `sudo easy_install pip && sudo pip install -r requirements.txt`  
- Linux (deb-based): `sudo easy_install pip && sudo apt-get install libssl-dev && sudo pip install -r requirements.txt` 
+ Linux (deb-based): `sudo easy_install pip && sudo apt-get install build-essential libssl-dev libffi-dev python-dev && sudo pip install -r requirements.txt` 
 
 2. Open the file `config.cfg` in your favorite text editor. Specify the users you wish to create in the `users` list.
 3. Start the deploy and follow the instructions: `./algo`