text: //Generates a letter-only (sms url friendly) key for ids
  
  const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
  
  module.exports = len => {
    let result = '';
    for (let i = 0; i < len; i++) {
      const pos = Math.floor(Math.random() * len);
      result += characters.slice(pos, pos + 1);
    }
    return result;
  };
  