Fixed problem with missing directories

src/main/java/at/ac/uibk/gitsearch/service/ExerciseService.java

@@ -312,6 +312,10 @@ public class ExerciseService {
     private void writeFile(File entryFile, ZipInputStream zipInputStream) throws IOException {
         byte[] buffer = new byte[1024];
 
+        if (!entryFile.getParentFile().exists()) {
+            Files.createDirectories(entryFile.getParentFile().toPath());
+        }
+
         try (FileOutputStream fos = new FileOutputStream(entryFile)) {
             int len;
             while ((len = zipInputStream.read(buffer)) > 0) {