comment to make MaxAge units more obvious

README.md

@@ -36,7 +36,7 @@ log.SetOutput(&lumberjack.Logger{
     Filename:   "/var/log/myapp/foo.log",
     MaxSize:    500, // megabytes
     MaxBackups: 3,
-    MaxAge:     28,
+    MaxAge:     28, //days
 })
 ```
 

example_test.go

@@ -13,6 +13,6 @@ func Example() {
 		Filename:   "/var/log/myapp/foo.log",
 		MaxSize:    500, // megabytes
 		MaxBackups: 3,
-		MaxAge:     28,
+		MaxAge:     28, // days
 	})
 }