added hash and equals overide

application/model/src/main/java/org/fuseri/model/dto/exercise/ExerciseDto.java

@@ -7,6 +7,8 @@ import lombok.Getter;
 import lombok.Setter;
 import org.fuseri.model.dto.common.DomainObjectDto;
 
+import java.util.Objects;
+
 @Getter
 @Setter
 public class ExerciseDto extends DomainObjectDto {
@@ -23,4 +25,26 @@ public class ExerciseDto extends DomainObjectDto {
 
     @NotBlank
     private String courseId;
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        ExerciseDto that = (ExerciseDto) o;
+
+        if (difficulty != that.difficulty) return false;
+        if (!Objects.equals(name, that.name)) return false;
+        if (!Objects.equals(description, that.description)) return false;
+        return Objects.equals(courseId, that.courseId);
+    }
+
+    @Override
+    public int hashCode() {
+        int result = name != null ? name.hashCode() : 0;
+        result = 31 * result + (description != null ? description.hashCode() : 0);
+        result = 31 * result + difficulty;
+        result = 31 * result + (courseId != null ? courseId.hashCode() : 0);
+        return result;
+    }
 }