Finish the System Cleanup feature.

rest/footprint_dao.go

@@ -118,3 +118,10 @@ func (this *FootprintDao) AvgCostBetweenTime(startTime time.Time, endTime time.T
 	return int64(cost)
 }
 
+
+//执行清理操作
+func (this *FootprintDao) Cleanup() {
+	this.logger.Info("[FootprintDao]执行清理：清除数据库中所有Footprint记录。")
+	db := CONTEXT.DB.Where("uuid is not null").Delete(Footprint{})
+	this.PanicError(db.Error)
+}