readme update

README.md

@@ -6,7 +6,7 @@ Correo is a .NET service for programmatically sending emails. Communication with
 
 It can be integrated with several types of mediators, the configuration being the following:
 
-```"SmtpMediator": "SendGrid" //.NET, MailKit, SendGrid```
+```"SmtpMediator": "SmtpClient", //SmtpClient, SendGrid, Mailgun```
 
 ## Mediators
 
@@ -18,8 +18,8 @@ It can be integrated with several types of mediators, the configuration being th
 The integration with SMTP servers can be done through two libraries (.NET / MailKit), and the configuration area looks like this:
 
 ```
-"SmtpMediator": "MailKit",
 "SmtpClient": {
+  "Package": "MailKit", //.NET, MailKit
   "Server": "smtp.gmail.com",
   "Port": "587",
   "UseAuthentication": true,
@@ -41,11 +41,22 @@ For this integration, the setup is very simple. All you need is an API Key gener
 
 ```
 "SmtpMediator": "SendGrid"
-"SmtpService": {
+"SendGrid": {
   "ApiKey": "xxxxxxxxxxx"
 }
 ```
 
+#### Mailgun
+Mailgun is an email automation service that allows you to send, receive, and track emails. It offers a free usage plan as well as a pay-as-you-go pricing model that is based on the number of emails sent per month.
+For this integration, the setup is very simple. All you need is an API Key generated from the [Mailgun](https://app.mailgun.com/) platform and the domain name configured in Mailgun. Afterwards, this keys will be configured in Correo as below:
+```
+"SmtpMediator": "Mailgun"
+"Mailgun": {
+  "ApiKey": "xxxxxxxxxxx",
+  "Domain": "xxxxxxxxxxx"
+}
+```
+
 ## Database
 The database is SQLite. It is created automatically at the first start of the service, if it is missing. The path where the database is stored can be configured as follows: