feat: 添加帮助功能

handler/help/help.go

@@ -0,0 +1,22 @@
+package help
+
+import (
+	"git.lxtend.com/qqbot/handler"
+	"git.lxtend.com/qqbot/model"
+)
+
+func init() {
+	handler.RegisterHandler("!help", help)
+}
+
+func help(msg model.Message) (reply model.Reply) {
+	helpInfo := `以下是支持的功能：`
+	for k, v := range handler.HelpInforms {
+		helpInfo += "\n" + k + " : " + v
+	}
+	return model.Reply{
+		ReplyMsg:       helpInfo,
+		ReferOriginMsg: false,
+		FromMsg:        msg,
+	}
+}