message: Show command help when given no arguments
diff: @@ -2,7 +2,7 @@ use std::env;
  use std::str::FromStr;
  use cache::get_wrangler_cache;
  -use clap::{App, Arg, SubCommand};
  +use clap::{App, AppSettings, Arg, SubCommand};
  use commands::HTTPMethod;
  use log::info;
  @@ -35,6 +35,7 @@ fn main() -> Result<(), failure::Error> {
  let matches = App::new(format!("{}{} wrangler", emoji::WORKER, emoji::SPARKLES))
  .version(env!("CARGO_PKG_VERSION"))
  .author("ashley g williams <ashley666ashley@gmail.com>")
  + .setting(AppSettings::ArgRequiredElseHelp)
  .subcommand(
  SubCommand::with_name("generate")
  .about(&*format!(
  