Developing a simple voting application

First, we are going to build the simplest voting application, simpler than the voting application example that comes with the Vyper software source code. Let's set up our Populus project directory:

$ virtualenv -p python3.6 voting-venv
$ source voting-venv/bin/activate
(voting-venv) $ pip install eth-abi==1.2.2
(voting-venv) $ pip install eth-typing==1.1.0
(voting-venv) $ pip install web3==4.7.2
(voting-venv) $ pip install -e git+https://github.com/ethereum/populus#egg=populus
(voting-venv) $ pip install vyper
(voting-venv) $ mkdir voting_project
(voting-venv) $ cd voting_project
(voting-venv) $ mkdir tests contracts
(voting-venv) $ cp ../voting-venv/src/populus/populus/assets/defaults.v9.config.json project.json

Then, add Vyper support to project.json by changing the value of the key compilation to the following:

"compilation": {
  ...