Observer pattern & Archipelago

src/main/java/com/bernard/nodecames/model/Grid.java

@@ -3,6 +3,7 @@ package com.bernard.nodecames.model;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
+import java.util.Set;
 import java.util.UUID;
 
 import org.hibernate.annotations.JdbcTypeCode;
@@ -10,12 +11,15 @@ import org.hibernate.type.SqlTypes;
 
 import jakarta.annotation.Nullable;
 import jakarta.persistence.AttributeConverter;
+import jakarta.persistence.CascadeType;
 import jakarta.persistence.Column;
 import jakarta.persistence.Convert;
 import jakarta.persistence.Embedded;
 import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
 import jakarta.persistence.Id;
 import jakarta.persistence.ManyToOne;
+import jakarta.persistence.OneToMany;
 import lombok.AllArgsConstructor;
 import lombok.Getter;
 import lombok.NoArgsConstructor;