add( moniker ) {
    const defSheet = FreshResume.default();
    const newObject =
      defSheet[moniker].history
      ? extend( true, {}, defSheet[ moniker ].history[0] )
      :
        moniker === 'skills'
        ? extend( true, {}, defSheet.skills.sets[0] )
        : extend( true, {}, defSheet[ moniker ][0] );

    this[ moniker ] = this[ moniker ] || [];
    if (this[ moniker ].history) {
      this[ moniker ].history.push(newObject);
    } else if (moniker === 'skills') {
      this.skills.sets.push(newObject);
    } else {
      this[ moniker ].push(newObject);
    }
    return newObject;
  }
Add work experience to the sheet.