Using Vagrant to setup a Wordpress test environment

https://premium.wpmudev.org/blog/vagrant-wordpress-test-environment/
I am following the instructions from the above link.

Now I try and run the following.
curl -L -o 'install.sh' http://bit.ly/1hBfq57 && curl -L -o 'Vagrantfile' http://bit.ly/1mE3Qt9 && vagrant up

and get the following error:
0curl: (60) SSL certificate problem: unable to get local issuer certificate

I have looked at the following link but am still not sure how to solve this.
https://curl.haxx.se/docs/sslcerts.html