make 'rails runner' show usage when run without any options

railties/lib/rails/commands/runner.rb

@@ -4,6 +4,10 @@
 options = { :environment => (ENV['RAILS_ENV'] || "development").dup }
 code_or_file = nil
 
+if ARGV.first.nil?
+  ARGV.push "-h"
+end
+
 ARGV.clone.options do |opts|
   script_name = File.basename($0)
   opts.banner = "Usage: runner [options] ('Some.ruby(code)' or a filename)"

railties/test/application/runner_test.rb

@@ -22,6 +22,10 @@ def teardown
       teardown_app
     end
 
+    def test_should_include_runner_in_shebang_line_in_help_without_option
+      assert_match "/rails runner", Dir.chdir(app_path) { `bundle exec rails runner` }
+    end
+
     def test_should_include_runner_in_shebang_line_in_help
       assert_match "/rails runner", Dir.chdir(app_path) { `bundle exec rails runner --help` }
     end