Initialized validator in user.js

It's been awhile since the last PR's!  Tony brought up recently a bug where users can no longer be created on the website.  Instead, "Send failed" shows up when trying to signup.  If this is reproduced locally, the terminal/command line shows an error in User.js line 10, saying that the reference to the variable "validator" is missing.

It looks as though one line in User.js that is meant to initialize the validator was dropped out somewhere along the way, and we haven't noticed it until recently.  This PR should re-include the line restore user creation functionality.