title: Send email on testing docker container with php and sendmail
body: <p>I'm on ubuntu 16.04. I have a (testing) docker (docker-compose) container running php 5.6 and apache 2.4.</p>
  
  <p>On the production platform (without docker) the mail is sent with sendmail.</p>
  
  <p>How to send test email on docker container (with sendmail)?</p>
  
  <p>Thanks in advance for responses.</p>