AC:

• Add @FF annotation and program the implementation using AOP (@Protected is a good example you can follow to help you out)
• @FF should accept an SpEL string that refers to one or more feature flags (e.g. duel && school).
  • Confirm that all the flags exists inside of a FeatureFlagManager class, else throw
  • If the expression evaluates to false, throw a ResponseStatusException
  • Else, run the annotated method as per usual