Update file README.md

To do this open the directory of this code in a terminal. If you cloned it to your home directory you should acces it via:    

`cd <name of dir you cloned to>`     

Then set up the environment here (this one sets up an environment called env).         

`python -m venv env`    

`python3 -m venv env`    

Now activate the environment:     

`source env/bin/activate`    

After this your command line should look like this `(env) <yourusername>@<nameofyourmachine>:/`