feat: register logic refactor

src/main/java/xin/merlin/myplayerbackend/mapper/PlayroomMapper.java

@@ -0,0 +1,9 @@
+package xin.merlin.myplayerbackend.mapper;
+
+import com.baomidou.mybatisplus.core.mapper.BaseMapper;
+import org.apache.ibatis.annotations.Mapper;
+import xin.merlin.myplayerbackend.entity.Playroom;
+
+@Mapper
+public interface PlayroomMapper extends BaseMapper<Playroom> {
+}