Send an email to the user when a recording is done processing

Had to add an email attribute to users to store their email to send the
notification. Will only send it for user rooms since they are the only
ones we know who to notify.

sample.env

@@ -17,6 +17,20 @@ BIGBLUEBUTTON_SECRET=8cd8ef52e8e101574e400365b55e11a6
 # the application when recordings are done).
 GREENLIGHT_USE_WEBHOOKS=false
 
+# The web site domain, needed for emails mostly
+GREENLIGHT_DOMAIN=localhost
+
+# SMTP configurations
+SMTP_FROM=email@gmail.com
+SMTP_SERVER=smtp.gmail.com
+SMTP_DOMAIN=gmail.com
+SMTP_PORT=587
+SMTP_USERNAME=email@gmail.com
+SMTP_PASSWORD=my-secret-password
+# SMTP_TLS=false
+# SMTP_AUTH=login
+# SMTP_STARTTLS_AUTO=true
+
 # OmniAuth
 TWITTER_ID=
 TWITTER_SECRET=