Add log system

log/log_test.go

@@ -0,0 +1,14 @@
+package log
+
+import (
+	"testing"
+)
+
+func TestLog(t *testing.T) {
+	Info("Test log.Infow", "value", 10)
+	Infof("Test log.Infof %d", 10)
+	Debugf("Test log.Debugf %d", 10)
+	Error("Test log.Error", "value", 10)
+	Errorf("Test log.Errorf %d", 10)
+	Warnf("Test log.Warnf %d", 10)
+}