Create User flow

[karllhughes]

Let's make the whole "create account" flow as a demonstration of our architecture.

• Webhook gets the sender phone number and message
• Create a Parser that:
  • Decides whether the input message is valid
  • Decides on the action to take
  • Parses the input(s)
  • Passes a response back to the webhook
• Create an Action that:
  • Creates a new user account with the username and phone number provided
  • Passes a status back to the webhook
• Create a Response Generator that:
  • Formats the status in a human readable way
  • Wraps the response string in a Twilio Message object
• Webhook will respond with the Twilio status

Also, consider throwing and handling errors:

• Invalid username (must be 3+ characters, only alphanumeric)
• User already exists
• Server errors