Add requirements to install

[pmoen-palominodb]

Please indicate that you need the MySQL client dev library and python dev library.
eg
For Ubuntu:
sudo apt-get install python-dev libmysqlclient-dev

You might want to show an example how to isolate this with virtual env
eg
git clone https://github.com/palominodb/python-int-overflow-check.git
mkdir python-int-overflow-check
virtual env
cd env
env/bin/pip install -r requirements.txt

[moss-palominodb]

Thanks for the suggestion. We have these instructions on newer tools, but not on older ones like this. I'll ensure they get added.