text: /**
   * author: Martin
   * define constants using in this project
   */
  
  var Constant	= {
      SERVER_ERR				: 'SERVER_ERR',
      QUERY_ERR 				: 'QUERY_ERR',
      EMPTY_DATA 				: 'EMPTY_DATA',
      FAILED_CODE				: 'FAILED',
      FAILED_LOG				: 'FAILED_LOG',
      NOT_FOUND				: 'NOT_FOUND',
      FORBIITEN				: 'NOT_FOUND',
      SUPPORT				    : 'SUPPORT',
      NOT_SUPPORT				: 'NOT_SUPPORT',
      OK_CODE					: 'OK',
      LOGINED					: 'LOGINED',
      MISMATCH_PARAMS			: 'MISMATCH_PARAMS',		//wrong parameters sending to server
      MISMATCH_SOCIAL_ID		: 'MISMATCH_SOCIAL_ID',		//wrong FB or Google ID sending to server
      UTF_8					: 'UTF-8',
      TRUE					: true,
      FALSE					: false,
      //
      NOT_DATA				: 'NOT_DATA',
      NOT_EXISTED				: 'NOT_EXISTED',
      NOT_MATH_PASSWORD		: 'NOT_MATH_PASSWORD',
      EXISTED					: 'EXISTED',
      //
      USERNAME_NOT_EXISTED    : "USERNAME_NOT_EXISTED",
      INFO_USER_NOT_EXISTED   : "INFO_USER_NOT_EXISTED",
      //
      USERNAME_AVAILABLE		: 'USERNAME_AVAILABLE',
      TYPE_MESSAGE            : {
          SINGLE  : "SINGLE",
          FILE    : "FILE",
          IMAGE   : "IMAGE",
          AUDIO   : "AUDIO",
          TEXT    : "TEXT"
      },
      isUseHTTPs : false,
      PRIV_KEY_PATH : '/etc/letsencrypt/live/staging.toidayhoc.com/privkey.pem',
      CERT_KEY_PATH : '/etc/letsencrypt/live/staging.toidayhoc.com/cert.pem'
  };
  //
  module.exports = Constant;