Slack bot to keep track of Items created and modified

[wilfriedE]

Create Slack Channel for FIRSTMastery
Implement a Slack bot that will post to Slack updates:

• New/Deleted Lessons
• New/Deleted Lesson Versions
• Promoted Lesson Versions (when a Lesson Version becomes primary Lesson's current version)
• New/Deleted Courses
• New/Deleted Tracks
  ...
  suggestions are welcome