functions.php

//* Enqueue Dashicons
add_action( 'wp_enqueue_scripts', 'enqueue_dashicons' );
function enqueue_dashicons() {
	wp_enqueue_style( 'dashicons' );
}

//* Add Twitter field in User Profile page in WP admin
function my_new_contactmethods( $contactmethods ) {
	$contactmethods['twitter'] = 'Twitter (w/o the @)';

	return $contactmethods;
}
add_filter( 'user_contactmethods', 'my_new_contactmethods', 10, 1 );

//* Create [twitter_link] shortcode
add_shortcode( 'twitter_link', 'gamajo_twitter_link_shortcode' );
function gamajo_twitter_link_shortcode() {
    $twitter_handle = ltrim( get_the_author_meta( 'twitter' ), '@' );

    if ( empty( $twitter_handle ) ) {
        return '';
    }

    return sprintf(
        '<span class="twitter"><a href="%s" target="_blank"><span class="dashicons dashicons-twitter"></span></a></span>',
        esc_url( 'https://twitter.com/' . $twitter_handle ),
        $twitter_handle
    );
}

//* Customize entry meta in the entry header
add_filter( 'genesis_post_info', 'sp_post_info_filter' );
function sp_post_info_filter( $post_info ) {
	if ( is_singular( 'post' ) ) {
		$post_info = 'by [post_author_posts_link] on [post_date] [twitter_link] [post_edit]';
	}
	return $post_info;
}