feat: add mathpixel

config/config.go

@@ -13,6 +13,12 @@ type Config struct {
 	UploadDir string         `mapstructure:"upload_dir"`
 	Limit     LimitConfig    `mapstructure:"limit"`
 	Aliyun    AliyunConfig   `mapstructure:"aliyun"`
+	Mathpix   MathpixConfig  `mapstructure:"mathpix"`
+}
+
+type MathpixConfig struct {
+	AppID  string `mapstructure:"app_id"`
+	AppKey string `mapstructure:"app_key"`
 }
 
 type LimitConfig struct {