Add virtualenv initialization script

.gitignore

 *.pyc
 *.sqlite
 *~
-env
+venv
 media
 local_settings.py
 docs/_build

load.sh

+#! /bin/sh
+
+# create virtual env
+# without --system-site-packages
+test -d venv || virtualenv venv/
+
+# install required dependencies
+./venv/bin/pip install -r requirements.txt
+
+# use `source venv/bin/activate`