添加log使用文档

Author: c-wind

doc/log_test.png

@@ -0,0 +1,53 @@
+## crab log  
+crab log 是一个轻量级log库，支持不同级别不同颜色输出，按天滚动输出日志文件等常用日志功能  
+
+## Example  
+[![Example Output](doc/log_test.png)](log/log_test.go)  
+
+```go
+package log 
+
+import (
+    "testing"
+    "time"
+)
+
+func TestLog(t *testing.T) {
+    Debug("default log begin")
+    Infof("%v test log", time.Now())
+
+    l := NewLogger()
+    l.Debug("logger 1111111111")
+    l.Info("logger 2222222222")
+    l.Warningf("logger 33333 %v", time.Now())
+    l.Errorf("logger color %v xxxxxx", time.Now().UnixNano())
+    l.SetColor(false)
+    l.Errorf("logger no color %v yyyyyy", time.Now().UnixNano())
+    Infof("%v default has color test log", time.Now())
+
+    l.SetOutputFile("./vvv.log").SetRolling(true)                                                                                                                                                                                                         
+    l.Info(time.Now())
+}
+
+```  
+
+## Installing
+
+### Using *go get*
+```bash
+    $ go get github.com/dearcode/crab/log  
+```
+After this command *log* is ready to use. Its source will be in:  
+```bash
+    $GOPATH/src/github.com/dearcode/crab/log  
+```
+
+You can use `go get -u` to update the package.  
+
+## Documentation  
+
+For docs, see http://godoc.org/github.com/dearcode/crab/log or run:  
+```bash
+    $ godoc github.com/dearcode/crab/log  
+```
+

log/README.md

@@ -6,12 +6,13 @@ import (
 )
 
 func TestLog(t *testing.T) {
-	Debug("default log begin 11111111")
-	Debugf("%s, %+v", "abc", mlog)
+	Debug("default log begin")
 	Infof("%v test log", time.Now())
 
 	l := NewLogger()
+	l.Debug("logger 1111111111")
 	l.Info("logger 2222222222")
+    l.Warningf("logger 33333 %v", time.Now())
 	l.Errorf("logger color %v xxxxxx", time.Now().UnixNano())
 	l.SetColor(false)
 	l.Errorf("logger no color %v yyyyyy", time.Now().UnixNano())