fix: Chat Backup 리턴 타입 등록

Author: ldhbenecia

chat/src/main/kotlin/com/benecia/lifetracker/chat/chatMessage/service/ChatMessageService.kt

@@ -12,7 +12,7 @@ class ChatMessageService(
         return chatMessageReader.getMessages(roomId)
     }
 
-    fun backupMessage(message: ChatMessage) {
+    fun backupMessage(message: ChatMessage): ChatMessage {
         return chatMessageWriter.backup(message)
     }
 }

chat/src/main/kotlin/com/benecia/lifetracker/chat/chatMessage/service/ChatMessageWriter.kt

@@ -6,7 +6,7 @@ import org.springframework.stereotype.Component
 class ChatMessageWriter(
     private val chatMessageRepository: ChatMessageRepository,
 ) {
-    fun backup(message: ChatMessage) {
+    fun backup(message: ChatMessage): ChatMessage {
         return chatMessageRepository.save(message)
     }
 }