Loop Category wordpress with pagination in page

Page.php

<?php get_header(); ?>

<h2>Posts</h2>

<?php

$paged = ( get_query_var(‘paged’) ) ? get_query_var(‘paged’) : 1;

$custom_args = array(
    ‘post_type’ => ‘post’,
    ‘posts_per_page’ => 2,
    ‘paged’ => $paged,
    ‘category_name’ => ‘extension’,
  );

$custom_query = new WP_Query( $custom_args ); ?>

<?php if ( $custom_query->have_posts() ) : ?>

  <!– the loop –>
  <?php while ( $custom_query->have_posts() ) : $custom_query->the_post(); ?>
    <article class=»loop»>
      <h3><?php the_title(); ?></h3>
      <div class=»content»>
        <?php the_excerpt(); ?>
      </div>
    </article>
  <?php endwhile; ?>
  <!– end of the loop –>

  <!– pagination here –>
  <?php
    if (function_exists(custom_pagination)) {
      custom_pagination($custom_query->max_num_pages,»»,$paged);
    }
  ?>

<?php wp_reset_postdata(); ?>

<?php else:  ?>
  <p><?php _e( ‘Sorry, no posts matched your criteria.’ ); ?></p>
<?php endif; ?>

<?php get_footer(); ?>

function.php

function custom_pagination($numpages = », $pagerange = », $paged=») {

  if (empty($pagerange)) {
    $pagerange = 2;
  }

  /**
   * This first part of our function is a fallback
   * for custom pagination inside a regular loop that
   * uses the global $paged and global $wp_query variables.
   *
   * It’s good because we can now override default pagination
   * in our theme, and use this function in default quries
   * and custom queries.
   */
  global $paged;
  if (empty($paged)) {
    $paged = 1;
  }
  if ($numpages == ») {
    global $wp_query;
    $numpages = $wp_query->max_num_pages;
    if(!$numpages) {
        $numpages = 1;
    }
  }

  /**
   * We construct the pagination arguments to enter into our paginate_links
   * function.
   */
  $pagination_args = array(
    ‘base’            => get_pagenum_link(1) . ‘%_%’,
    ‘format’          => ‘page/%#%’,
    ‘total’           => $numpages,
    ‘current’         => $paged,
    ‘show_all’        => False,
    ‘end_size’        => 1,
    ‘mid_size’        => $pagerange,
    ‘prev_next’       => True,
    ‘prev_text’       => __(‘&laquo;’),
    ‘next_text’       => __(‘&raquo;’),
    ‘type’            => ‘plain’,
    ‘add_args’        => false,
    ‘add_fragment’    => »
  );

  $paginate_links = paginate_links($pagination_args);

  if ($paginate_links) {
    echo «<nav class=’custom-pagination’>»;
      echo «<span class=’page-numbers page-num’>Page » . $paged . » of » . $numpages . «</span> «;
      echo $paginate_links;
    echo «</nav>»;
  }

}
?>

Fuente: http://callmenick.com/post/custom-wordpress-loop-with-pagination