add reCAPTCHA tags in devise registration view

[shalstein]

In order for the reCAPTCHA to work, you will need to generate two keys from https://www.google.com/recaptcha/admin#list

Then use them to set these environment variables in your dotenv file

export RECAPTCHA_SITE_KEY = YOURSITEKEY
export RECAPTCHA_SECRET_KEY = YOURSECERTKEY

[sophiedeziel]

Yay! You made it! I'll have a look to it soon

[shalstein]

closes #302