Add usage section to README

README.md

@@ -6,10 +6,37 @@ Every morning, get the content of your favorite trello board by email
 
 ## Installation
 
-Make sure you have Go installed, then type :
+Make sure you have Go installed, then type:
 
     go install github.com/glenux/trello2mail-go/...
 
+It will install Trello2Mail binary in `$GOPATH/bin`
+
+
+## Usage
+
+Prepare your environment with the following variables
+
+```
+EMAIL_FROM:    no-reply@example.com
+EMAIL_TO:      me@example.com
+EMAIL_SUBJECT: "Daily mail for YYYYYY"
+TRELLO_URL:    https://trello.com/b/xxxxx/yyyy
+TRELLO_TOKEN:  xxxxxxxxxxxxxx
+SMTP_HOSTNAME: smtp.example.com
+SMTP_USERNAME: foobar@example.com
+SMTP_PASSWORD: securefoobar
+SMTP_PORT:   587
+# SMTP_AUTH_TYPE accepts either "none", "plain" or "login"
+SMTP_AUTH_TYPE: plain 
+# SMTP_SECURITY_TYPE accepts either "none", "tls" or "starttls"
+SMTP_SECURITY_TYPE: tls
+```
+
+Then run the program:
+
+    $GOPATH/bin/trello2mail
+
 
 ## Contributing
 

docker-compose.example.yml

@@ -12,6 +12,8 @@ services:
       SMTP_USERNAME: foobar@example.com
       SMTP_PASSWORD: securefoobar
       SMTP_PORT:   587
-      SMTP_AUTH_TYPE: plain
+      # SMTP_AUTH_TYPE accepts either "none", "plain" or "login"
+      SMTP_AUTH_TYPE: plain 
+      # SMTP_SECURITY_TYPE accepts either "none", "tls" or "starttls"
       SMTP_SECURITY_TYPE: tls