Tested in big data set

buisnesslogic/src/main/java/com/plannaplan/services/AssignmentService.java

@@ -89,13 +89,13 @@ public class AssignmentService {
                     final Groups group = a.getGroup();
                     if (group.getCapacity() > group.getRegisteredStudents().size()) {
                         e.claimGroup(group);
-                        this.userService.save(e);
                         accepted.add(group);
                     } else {
                         removed.add(group);
                     }
                 });
             }
+            this.userService.save(e);
             this.emailService.sendAcceptationResult(e, new EmailAcceptedData(accepted, removed));
         });
     }

buisnesslogic/src/main/java/com/plannaplan/services/UserService.java

@@ -154,6 +154,10 @@ public class UserService {
         return this.repo.getAllByRole(UserRoles.ADMIN).size() > 0;
     }
 
+    public void saveAll(List<User> users) {
+        this.repo.saveAll(users);
+    }
+
     /**
      * get students sorted by their ranking
      *