code: function LogStream(options) {
  
      this.model = options.model || false;
  
      if (!this.model) {
          throw new Error('[LogStream] - Fatal Error - No mongoose model provided!');
      }
  
      Writable.call(this, options);
  }
docs: the LogStream constructor.
  it inherits all methods of a writable stream
  the constructor takes a options object. A important field is the model, the model will
  be used for saving the log entry to the mongo db instance.
  @param options
  @constructor