Add AddHook method for logger

logger.go

@@ -315,3 +315,9 @@ func (logger *Logger) level() Level {
 func (logger *Logger) SetLevel(level Level) {
 	atomic.StoreUint32((*uint32)(&logger.Level), uint32(level))
 }
+
+func (logger *Logger) AddHook(hook Hook) {
+	logger.mu.Lock()
+	defer logger.mu.Unlock()
+	logger.Hooks.Add(hook)
+}