added 500 error-handler
added 500 error-handler

foss-transportationmodeling/rettina-server,foss-transportationmodeling/rettina-server,foss-transportationmodeling/rettina-server,foss-transportationmodeling/rettina-server,foss-transportationmodeling/rettina-server,foss-transportationmodeling/rettina-server