Add new file

test.md

+
+### test
+
+```mermaid
+erDiagram
+	t_device||--||t_area:located
+	t_area||--||t_time_zone:belongsTo
+	t_user||--||t_time_zone:belongsTo
+	t_time_zone {
+		string time_zone_name "时区名称"
+		bigint timediff_from_utc0 "相对UTC+0的时间差"
+	}
+	t_device {
+		string device_sn
+		bigint area_id "地区ID"
+	}
+	t_area {
+		string area_name "地区名称"
+		bigint time_zone_id "时区ID"
+	}
+	t_user {
+		bigint time_zone_id "时区ID"
+	}
+```
\ No newline at end of file