Don't let non-admin users access wp-admin

functions.php

/*-----------------------------------------------------------------------------------*/
/*	Don't let non-admin users access wp-admin.
/*-----------------------------------------------------------------------------------*/
add_action( 'init', 'blockusers_init' );
function blockusers_init() {
	if ( is_admin() && ! current_user_can( 'administrator' ) ) {
		wp_redirect( home_url() );
		exit;
	}
}