POST /api/exercise/new-user
POST /api/exercise/add
GET users's exercise log: GET /portfolio/api/exercise/log?username=Dave [or userId={userId}][&from][&to][&limit]
GET /portfolio/api/exercise/log?username=Dave [or userId={userId}][&from][&to][&limit]
{ } = required, [ ] = optional
from, to = dates (yyyy-mm-dd); limit = number