Merge branch 'Fix-get-next-counter' into 'development'

Use interval time when for request count.

See merge request !188

src/main/java/nl/tudelft/ewi/queue/model/Lab.java

@@ -743,7 +743,7 @@ public class Lab implements Serializable {
 	 */
 	public LocalDateTime getAcceptInterval() {
 		if (this.getDirection().equals(Direction.STUDENT_VISIT_TA)) {
-			return LocalDateTime.now().plusMinutes(this.getSlot().durationOfSlot());
+			return LocalDateTime.now().plusMinutes(this.intervalTime);
 		} else {
 			return LocalDateTime.now().plusMinutes(1L);
 		}