When an unexpected exception is caught, tell the administrator to read the log...

When an unexpected exception is caught, tell the administrator to read the log file for more information about the error. This should make things less confusing for developers who are new to Rails.
Signed-off-by: NMichael Koziarski <michael@koziarski.com>

railties/html/500.html

@@ -25,6 +25,8 @@
   <div class="dialog">
     <h1>We're sorry, but something went wrong.</h1>
     <p>We've been notified about this issue and we'll take a look at it shortly.</p>
+    <p><small>(If you're the administrator of this website, then please read
+    the log file "<%=h RAILS_ENV %>.log" to find out what went wrong.)</small></p>
   </div>
 </body>
 </html>
\ No newline at end of file

railties/test/error_page_test.rb

+require 'abstract_unit'
+require 'action_controller'
+require 'action_controller/test_process'
+
+RAILS_ENV = "test"
+
+module Rails
+  def self.public_path
+    File.expand_path(File.join(File.dirname(__FILE__), "..", "html"))
+  end
+end
+
+class ErrorPageController < ActionController::Base
+  def crash
+    raise StandardError, "crash!"
+  end
+end
+
+ActionController::Routing::Routes.draw do |map|
+  map.connect ':controller/:action/:id'
+end
+
+class ErrorPageControllerTest < Test::Unit::TestCase
+  def setup
+    @controller = ErrorPageController.new
+    @request    = ActionController::TestRequest.new
+    @response   = ActionController::TestResponse.new
+
+    ActionController::Base.consider_all_requests_local = false
+  end
+
+  def test_500_error_page_instructs_system_administrator_to_check_log_file
+    get :crash
+    expected_log_file = "#{RAILS_ENV}.log"
+    assert_not_nil @response.body.index(expected_log_file)
+  end
+end