keywords() {
    let flatSkills = [];
    if (this.skills) {
      if (this.skills.sets) {
        flatSkills = this.skills.sets.map(sk => sk.skills).reduce( (a,b) => a.concat(b));
      } else if (this.skills.list) {
        flatSkills = flatSkills.concat( this.skills.list.map(sk => sk.name) );
      }
      flatSkills = _.uniq(flatSkills);
    }
    return flatSkills;
  }
Return a unique list of all skills declared in the resume.