add entity

src/main/java/ntnu/idatt2016/v233/SmartMat/entity/Group.java

+package ntnu.idatt2016.v233.SmartMat.entity;
+
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+@Entity(name = "groups")
+@Data
+public class Group {
+
+    @Id
+    @Column(name = "group_id")
+    long groupId;
+
+    @Column(name = "level")
+    int level;
+
+    @Column(name = "points")
+    int points;
+    
+    @Column(name = "group_name")
+    String groupName;
+}