componentWillReceiveProps(nextProps) {
    if (this.state.id !== nextProps.match.params.id && nextProps.homepage.categories !== null) {
      this.setState(
        {
          category: nextProps.homepage.categories.find(
            cat => cat.id == nextProps.match.params.id
          ),
          courses: [],
          count: 0
        },
        this.search(0, nextProps.match.params.id)
      );
    }
  }