backend hanwatts prediction model web interface

Merge pull request #14 in UPRFIR/backend-hanwatts-prediction-model-web-interface from UPRFIR-89-Route-Maken-Voor-Voorspelling-Energiegebruik to development

* commit '3d995b51dd0ca92007585f1c05ea6217728bb85c':
  mini readme update
  save predictions to the database
  wat error handling en documentatie
  sends back dummy data