add better generate

Signed-off-by: Jess Frazelle <acidburn@microsoft.com>

examples/busybox/generate.go

@@ -0,0 +1,18 @@
+// +build ignore
+
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/genuinetools/binctr/container"
+)
+
+// Pulls an image and saves the binary data in the container package bindata.go.
+func main() {
+	if err := container.EmbedImage("busybox"); err != nil {
+		fmt.Fprintf(os.Stderr, "embed image failed: %v\n", err)
+		os.Exit(1)
+	}
+}