// My pseudo-code routes:
GET ALL gym workouts "/gymworkouts"
GET gym workouts BY ID "/gymworkouts/:id"
GET ALL muscle groups "/musclegroups"
GET specific muscle group: "/musclegroups/:id"
GET ALL gym workouts BY muscle group "/musclegroups /:id/gymworkouts"
GET gym workout BY muscle group "/musclegroups /:id/gymworkouts/:id"
POST new gym workouts "/gymworkouts"