low case file extension

mediaendpoint.go

@@ -59,7 +59,7 @@ func HandleMedia(w http.ResponseWriter, r *http.Request) {
 				}
 			}
 		}
-		fileName += fileExtension
+		fileName += strings.ToLower(fileExtension)
 		location, err := SelectedMediaStorage.Upload(fileName, file)
 		if err != nil {
 			w.WriteHeader(http.StatusInternalServerError)