Prevent spam users from registering

[ColeDCrawford]

We have several hundred spam users on dev since open signups were allowed.

[ColeDCrawford]

[rsinghal]

@lukehollis This is high priority - it should be addressed ASAP or we will need to disable signups.

[ColeDCrawford]

We are up to ~700 spam users.

[rsinghal]

@npicardo @lukehollis We are going to have to disable signups until this gets resolved. I also see that it allows for the same email address to be registered for different usernames, which should also be fixed.

[lukehollis]

To address this, I'll try integrating the https://pypi.org/project/django-recaptcha/ package unless anyone has another preference.

[lukehollis]

Addressed in #160 -- to configure, now the secure.py.example has support for recaptcha fields:

[lukehollis]

Additionally, you may need to add your dev domains on your local environment to your keys.

[rsinghal]

Not working in the PR