ADD: API Endpoint test for the Goal POST and GET Endpoint

[tannerwheeler]

GIVEN: I'm an engineer contributing to the PowerPlay repo
WHEN: I make changes to the backend directory
THEN: I see function validation on each PR for the Goal Endpoint

Acceptance Criteria

• For POST of Goal

  • Input: Correct data for a new Goal. Output: Status Code 201 is returned.
  • Input: Incorrect data for a new Goal. Output: Status Code 400 is returned.

• For GET of Goal

  • Input: Correct data for getting all Goals. Output: Status Code 200 is returned.
  • Input: Incorrect data for getting all Goals. Output: Status Code 400 is returned.

• Test Passes if all output pass, but Fails if one output fails.

[MichaelPHanks]

I can work on this one