Add '-h, --help' flag to print help message then exit

cmd/tests.sh

@@ -14,6 +14,9 @@ PATH=`pwd`:$PATH
 
 test "$(tw --version)" = "v$FAKE_VERSION"
 
+tw --help
+test $? -eq 0
+
 tw create_profile data
 cd data
 

cmd/twitter/helpers.go

@@ -51,6 +51,9 @@ This application downloads tweets from twitter and saves them in a SQLite databa
           <TARGET> is the search query.  Should be wrapped in quotes if it has spaces.
 
 <flags>:
+    -h, --help
+          Print this message, then exit.
+
     -v, --version
           Print the version number and exit.
 

cmd/twitter/main.go

@@ -28,6 +28,9 @@ func main() {
 	how_many := flag.Int("n", 50, "???")
 	flag.IntVar(how_many, "number", 50, "???")
 
+	help := flag.Bool("help", false, "???")
+	flag.BoolVar(help, "h", false, "???")
+
 	flag.Parse()
 	args := flag.Args()
 
@@ -40,6 +43,10 @@ func main() {
 		os.Exit(0)
 	}
 
+	if *help {
+		die("", true, 0)
+	}
+
 	if len(args) < 2 {
 		die("", true, 1)
 	}