database configuration only via PG* env variables and MQTT password only via configured env var

src/udi/database/database.go

@@ -14,9 +14,10 @@ type DatabaseHandle struct {
   dbh *gorm.DB 
 }
 
-func NewDatabaseHandle(dsn string) *DatabaseHandle {
+func NewDatabaseHandle() *DatabaseHandle {
   var db DatabaseHandle
-  conn, err := gorm.Open(postgres.Open(dsn))
+  // inject the whole database configuration via the well-known PG* env variables
+  conn, err := gorm.Open(postgres.Open(""))
   if err != nil {
     log.Printf("Unable to open database connection: %s", err)
     db.initialized = false