Fix warning in Preparation

src/main/lombok/org/leumasjaffe/recipe/model/Preparation.java

@@ -12,9 +12,10 @@ import com.fasterxml.jackson.annotation.JsonIgnore;
 
 import lombok.AllArgsConstructor;
 import lombok.Data;
+import lombok.EqualsAndHashCode;
 import lombok.NoArgsConstructor;
 
-@Data @AllArgsConstructor @NoArgsConstructor
+@Data @AllArgsConstructor @NoArgsConstructor @EqualsAndHashCode(callSuper=false)
 public class Preparation extends Observable.Instance implements RecipeComponent {
 	Duration duration;
 	@JsonIgnore Supplier<Collection<Ingredient>> producer = Collections::emptyList;