Send notification to users when new broadcast is created

[aonomike]

• I'm submitting a ...

  • feature request

• What is the current behavior?
  When a user creates a new broadcast, nobody is notified.

• What is the expected behavior?
  It would be nice to send an email/slack notification informing that a new broadcast has been created.

• What is the motivation / use case for changing the behavior?
  Its nice to know whenever a new broadcast is created.
  It would be nice for auditing descriptions

• If you want to request a whole new feature, please provide a user story (otherwise delete):

  • As a moderator
  • I want be notified when a new broadcast is created
  • So that I can audit the description and prevent spamming/trolling

• What could be a possible solution? (not obligatory)
  Send an email to every user who ever created a broadcast, assuming they are willing to audit.

[faithngetich]

@aonomike should we notify users who've created broadcast before or only the moderators?
cc: @roschaefer