Updated build usage

commands.go

@@ -131,7 +131,7 @@ func (cli *DockerCli) CmdInsert(args ...string) error {
 }
 
 func (cli *DockerCli) CmdBuild(args ...string) error {
-	cmd := Subcmd("build", "[OPTIONS] PATH | -", "Build a new container image from the source code at PATH")
+	cmd := Subcmd("build", "[OPTIONS] PATH | URL | -", "Build a new container image from the source code at PATH")
 	tag := cmd.String("t", "", "Tag to be applied to the resulting image in case of success")
 	if err := cmd.Parse(args); err != nil {
 		return nil