updated README and added reference

README.md

@@ -296,6 +296,7 @@ The built-in logging formatters are:
   without colors.
   * *Note:* to force colored output when there is no TTY, set the `ForceColors`
     field to `true`.
+  * *Note:* to force no colored output set the `DisableColors` field to `true`
 * `logrus.JSONFormatter`. Logs fields as JSON.
 
 Third party logging formatters:

text_formatter.go

@@ -35,7 +35,7 @@ func (f *TextFormatter) Format(entry *Entry) ([]byte, error) {
 
 	prefixFieldClashes(entry)
 
-	if (f.ForceColors || IsTerminal()) && !DisableColors {
+	if (f.ForceColors || IsTerminal()) && !f.DisableColors {
 		levelText := strings.ToUpper(entry.Data["level"].(string))[0:4]
 
 		levelColor := blue