feat: Channel Entity 생성 (#1)

classmate-backend-main/classmate/src/main/java/devteamOne/classmate/channel/domain/Channel.java

@@ -0,0 +1,37 @@
+package devteamOne.classmate.channel.domain;
+
+import devteamOne.classmate.participant.domain.Participant;
+import devteamOne.classmate.question.domain.Question;
+import devteamOne.classmate.survey.domain.Survey;
+import devteamOne.classmate.user.domain.User;
+import jakarta.persistence.*;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+
+@Entity
+public class Channel {
+
+  @Id
+  @GeneratedValue(strategy = GenerationType.IDENTITY)
+  private Long id;
+
+  private String name;
+
+  private String code;
+
+  private LocalDateTime createdAt;
+
+  @ManyToOne(fetch = FetchType.LAZY)
+  @JoinColumn(name = "user_id")
+  private User user;
+
+  @OneToMany(mappedBy = "channel")
+  private List<Question> questionList = new ArrayList<>();
+
+  @OneToMany(mappedBy = "channel")
+  private List<Survey> surveyList = new ArrayList<>();
+
+  @OneToMany(mappedBy = "channel")
+  private List<Participant> participantList = new ArrayList<>();
+}