[IMP] mail_tracking_mailgun: Improve README

mail_tracking_mailgun/README.rst

@@ -6,13 +6,20 @@
 Mail tracking for Mailgun
 =========================
 
-This module integrates mail_tracking events with Mailgun webhooks
+This module integrates mail_tracking events with Mailgun webhooks.
+
+Mailgun (https://www.mailgun.com/) is a service that provides an e-mail 
+sending infrastructure through an SMTP server or via API. You can also 
+query that API for seeing statistics of your sent e-mails, or provide 
+hooks that processes the status changes in real time, which is the 
+function used here.
 
 Configuration
 =============
 
 You must configure Mailgun webhooks in order to receive mail events:
-1. Got a Mailgun account and validate your sending domain
+
+1. Got a Mailgun account and validate your sending domain.
 2. Go to Webhook tab and configure this URL for each event you want to track:
 
 .. code:: html
@@ -20,19 +27,27 @@ You must configure Mailgun webhooks in order to receive mail events:
    https://<your_domain>/mail/tracking/all/<your_database>
 
 Replace '<your_domain>' by your Odoo install domain name
-and '<your_database>' by your database name
+and '<your_database>' by your database name.
 
 In order to validate Mailgun webhooks you have to save Mailgun api_key in
 a system parameter named 'mailgun.apikey'. You can find Mailgun api_key in your
-validated sending domain
+validated sending domain.
 
 Usage
 =====
 
+In your mail tracking status screens (explained on module *mail_tracking*), you will
+see a more accurate information, like the 'Received' or 'Bounced' status, which are
+not usually detected by normal SMTP servers.
+
 .. image:: https://odoo-community.org/website/image/ir.attachment/5784_f2813bd/datas
    :alt: Try me on Runbot
    :target: https://runbot.odoo-community.org/runbot/205/8.0
 
+Known issues / Roadmap
+======================
+
+* There's no support for more than one Mailgun mail server.
 
 Bug Tracker
 ===========