Slack.com Webhook Integration (PHP) - Simple snippet which tells you, how to build your payload array.

slack.php

<?php 

        //Options
        $token    = 'YOUR_TOKEN_HERE';
        $domain   = 'YOUR_SLACK_DOMAIN_GOES_HERE';

        $channel  = '#general';
        $bot_name = 'Webhook';
        $icon     = ':alien:';
        $message  = 'Your message';

        $attachments = array([
            'fallback' => 'Lorem ipsum',
            'pretext'  => 'Lorem ipsum',
            'color'    => '#ff6600',
            'fields'   => array(
                [
                    'title' => 'Title',
                    'value' => 'Lorem ipsum',
                    'short' => true
                ],
                [
                    'title' => 'Notes',
                    'value' => 'Lorem ipsum',
                    'short' => true
                ]
            )
        ]);

        $data = array(
            'channel'     => $channel,
            'username'    => $bot_name,
            'text'        => $message,
            'icon_emoji'  => $icon,
            'attachments' => $attachments
        );

        $data_string = json_encode($data);

        $ch = curl_init('https://'.$domain.'.slack.com/services/hooks/incoming-webhook?token='.$token);
            curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
            curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
            curl_setopt($ch, CURLOPT_HTTPHEADER, array(
                'Content-Type: application/json',
                'Content-Length: ' . strlen($data_string))
            );

        //Execute CURL
        $result = curl_exec($ch);

        return $result;        

 ?>