fixed damaged deleting slots, see #5

src/main/resources/templates/lesson/item.html

@@ -30,7 +30,8 @@
 						<div class="col-sm-9">
 							<button type="submit" class="btn btn-outline-success">Speichern</button>&nbsp;
 							<a th:href="@{/}" class="btn btn-outline-secondary">Abbrechen</a>&nbsp;
-							<a th:href="@{/lesson/{id}/remove(id=${bean.pkLesson})}" class="btn btn-outline-danger">Löschen</a>
+							<a th:href="@{/lesson/{id}/remove(id=${bean.pkLesson})}" class="btn btn-outline-danger">Zuordnung löschen</a>
+							<a th:href="@{/slot/{id}(id=${bean.fkSlot})}" class="btn btn-outline-warning">Termin bearbeiten</a>
 						</div>
 					</div>
 				</form>