Added subrouter for subpath support

main.go

@@ -16,8 +16,15 @@ func main() {
 	r := mux.NewRouter()
 	r.StrictSlash(true)
 
-	setupApi(r)
-	setupFrontend(r)
+	var subrouter *mux.Router
+	if config.Prefix != "" {
+		r.PathPrefix(config.Prefix).Subrouter()
+	} else {
+		subrouter = r
+	}
+
+	setupApi(subrouter)
+	setupFrontend(subrouter)
 
 	db, err := database.NewSqlite3Connection(config.DatabaseFile)
 	if err != nil {