Updated README.md.

README.md

@@ -23,8 +23,8 @@ You will find the binary in `$GOPATH/bin` or, if set, `$GOBIN`.
 
 ## usage
 
-You can either pipe a programs output to `go-sendxmpp` or write in your terminal (put \^D in a new
-line to finish).
+You can either pipe a programs output to `go-sendxmpp`, write in your terminal (put \^D in a new
+line to finish) or send the input from a file (`-m` or `--message`).
 
 The account data is expected at `~/.sendxmpprc` if no other configuration file location is specified with
 `-f` or `--file`. The configuration file is expected to be in the following format: