<?php

function ab_social_costumizer( $wp_customize ) {
    $wp_customize->add_section('social_media',
        array(
            'title' => 'Social Media',
            'description' => 'This is a settings section.',
            'priority' => 9999,
        )
    );

    $wp_customize->add_setting('facebook', array(
        'default' => '',
        'sanitize_callback' => 'ab_sanitize_input' )
    );
    $wp_customize->add_control('facebook',
        array(
            'label' => 'Facebook',
            'section' => 'social_media',
            'type' => 'text',
            'settings' => 'facebook'
        )
    );

    $wp_customize->add_setting('google_plus', array(
        'default' => '',
        'sanitize_callback' => 'ab_sanitize_input' )
    );
    $wp_customize->add_control('google_plus',
        array(
            'label' => 'Google+',
            'section' => 'social_media',
            'type' => 'text',
            'settings' => 'google_plus'
        )
    );

    $wp_customize->add_setting('twitter', array(
        'default' => '',
        'sanitize_callback' => 'ab_sanitize_input' )
    );
    $wp_customize->add_control('twitter',
        array(
            'label' => 'Twitter',
            'section' => 'social_media',
            'type' => 'text',
            'settings' => 'twitter'
        )
    );

}
add_action( 'customize_register', 'ab_social_costumizer' );