Add missing recipe details

[Livshitz]

There are few high-level challenges I've listed here.
Help is needed to add more in-details description, like in the Email Scheduler recipe for instance.

Format:

Context:
Provide some background to the challenge to create a guided scenario in which the reader would solve. Try to tell a story.

Recipe:
What components or behaviors are expected to be seen in the result.

Validation:
Actual steps/conditions that could help the reader make sure his solution answers the challenge.