implement GET /visualizations/:visualization_id/overlays
implement GET /visualizations/:visualization_id/overlays

bloomberg/cartodb,UCL-ShippingGroup/cartodb-1,CartoDB/cartodb,splashblot/dronedb,splashblot/dronedb,UCL-ShippingGroup/cartodb-1,nyimbi/cartodb,thorncp/cartodb,codeandtheory/cartodb,splashblot/dronedb,codeandtheory/cartodb,DigitalCoder/cartodb,DigitalCoder/cartodb,CartoDB/cartodb,thorncp/cartodb,nuxcode/cartodb,codeandtheory/cartodb,bloomberg/cartodb,future-analytics/cartodb,bloomberg/cartodb,UCL-ShippingGroup/cartodb-1,DigitalCoder/cartodb,dbirchak/cartodb,raquel-ucl/cartodb,codeandtheory/cartodb,nuxcode/cartodb,nyimbi/cartodb,dbirchak/cartodb,bloomberg/cartodb,splashblot/dronedb,bloomberg/cartodb,DigitalCoder/cartodb,thorncp/cartodb,future-analytics/cartodb,dbirchak/cartodb,future-analytics/cartodb,nuxcode/cartodb,thorncp/cartodb,future-analytics/cartodb,dbirchak/cartodb,raquel-ucl/cartodb,future-analytics/cartodb,CartoDB/cartodb,CartoDB/cartodb,nyimbi/cartodb,raquel-ucl/cartodb,nyimbi/cartodb,thorncp/cartodb,splashblot/dronedb,CartoDB/cartodb,raquel-ucl/cartodb,nuxcode/cartodb,nuxcode/cartodb,raquel-ucl/cartodb,nyimbi/cartodb,UCL-ShippingGroup/cartodb-1,UCL-ShippingGroup/cartodb-1,DigitalCoder/cartodb,dbirchak/cartodb,codeandtheory/cartodb