Made PDFs not editable after export

Author: Just1Developer

src/main/java/ui/export/PDFCompiler.java

@@ -110,6 +110,9 @@ private static Optional<String> writeToPDF(PDDocument document, Global global, M
 		form.getField("Summe").setValue(timeSum.toString()); // Total time worked
 		form.getField("Urlaub anteilig").setValue(timeVacation.toString()); // Total time of Vacation
 
+		// Lock document
+		form.flatten();
+
 		// Save the filled document
 		document.save(targetFile);
 		document.close();