feat: 팔로우 도메인 Entity 생성 (#75)

src/main/java/com/depromeet/domain/relation/dao/MemberRelationRepository.java

@@ -0,0 +1,6 @@
+package com.depromeet.domain.relation.dao;
+
+import com.depromeet.domain.relation.domain.MemberRelation;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface MemberRelationRepository extends JpaRepository<MemberRelation, Long> {}

src/main/java/com/depromeet/domain/relation/domain/MemberRelation.java

@@ -0,0 +1,40 @@
+package com.depromeet.domain.relation.domain;
+
+import com.depromeet.domain.common.model.BaseTimeEntity;
+import com.depromeet.domain.member.domain.Member;
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.Table;
+import jakarta.persistence.UniqueConstraint;
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@Entity
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@Table(
+        uniqueConstraints = {
+            @UniqueConstraint(
+                    name = "member_relation_uk",
+                    columnNames = {"follower_id", "following_id"})
+        })
+public class MemberRelation extends BaseTimeEntity {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "member_relation_id")
+    private Long id;
+
+    @ManyToOne
+    @JoinColumn(name = "follower_id")
+    private Member follower;
+
+    @ManyToOne
+    @JoinColumn(name = "following_id")
+    private Member following;
+}