session plan output format

session_plan:
  id: int
  level_id: int
  phase_number: int
  phase: string
  position: int
  session_plan_exercises:
    [
      {
        id: int
        position: int
        session_plan_id: int
        set_number: int
        station_id: int
        created_at: datetime
        updated_at: datetime
        exercise: 
          {
            ...
          }
      },
      {
        ...
      }
    ]

also add workout_id to session_plan

also add side to session_plan_exercise