Improve and add test for Rake task integration

+Simplify README's explanation of integrations
+Make Rake integration automatic
+Remove TODO (it has an issue now)

Monkey patching #execute isn't as nice as patching #display_error_message, so we'll do that instead. I think monkey patching #execute may also cause Raven to not catch errors called with Rake's #invoke method.

Author: nateberkopec

README.md

@@ -33,10 +33,6 @@ You'll still want to ensure you've disabled anything that would prevent errors f
 config.action_dispatch.show_exceptions = false # this is the default setting in production
 ```
 
-#### Delayed::Job
-
-No extra configuration required. Usage of [delayed-plugins-raven](https://github.com/qiushihe/delayed-plugins-raven) gem is deprecated.
-
 ### Rack
 
 Add ```use Raven::Rack``` to your ```config.ru``` or other rackup file (this is automatically inserted in Rails).
@@ -45,14 +41,9 @@ Add ```use Raven::Rack``` to your ```config.ru``` or other rackup file (this is
 
 Like any other Rack middleware, add ```use Raven::Rack``` to your Sinatra app.
 
-### Sidekiq
-
-Raven includes [Sidekiq middleware](https://github.com/mperham/sidekiq/wiki/Middleware) which takes
-care of reporting errors that occur in Sidekiq jobs. To use it, just ```require 'raven/sidekiq'``` after you require Sidekiq. If you are using Sidekiq with Rails, just put this require somewhere in the initializers.
-
-### Rake
+### Sidekiq, Delayed::Job and Rake
 
-To report errors within rake tasks, require `raven/rake`. Under Rails, you should place this in an initializer.
+Raven works out-of-the-box with all these tools!
 
 ## Capturing Events
 

lib/raven/base.rb

@@ -207,11 +207,13 @@ def rack_context(env)
 
     # Injects various integrations
     def inject
-      # TODO(dcramer): integrations should have a way to opt-out
       require 'raven/integrations/delayed_job' if defined?(::Delayed::Plugin)
       require 'raven/railtie' if defined?(::Rails::Railtie)
       require 'raven/sidekiq' if defined?(Sidekiq)
-      require 'raven/tasks' if defined?(Rake)
+      if defined?(Rake)
+        require 'raven/rake'
+        require 'raven/tasks'
+      end
     end
 
     # For cross-language compat

lib/raven/rake.rb

@@ -1,16 +1,13 @@
 require 'raven'
 require 'rake/task'
 
-# Monkey patch Rake::Task#execute to capture and report exceptions on sentry
-# Include this file in an initializer 
 module Rake
-  class Task
-    alias :orig_execute :execute
-    def execute(args = nil)
-      Raven.capture :logger => 'rake', :tags => { 'rake_task' => @name } do
-        orig_execute(args)
-      end
+  class Application
+    alias :orig_display_error_messsage :display_error_message
+    def display_error_message(ex)
+      Raven.capture_exception ex, :logger => 'rake', :tags => { 'rake_task' => @name }
+      orig_display_error_messsage(ex)
     end
   end
 end
- 
+

spec/raven/rake_spec.rb

@@ -0,0 +1,11 @@
+require 'rake'
+
+describe 'Rake tasks' do
+
+  it 'should capture exceptions in Rake tasks' do
+    exception = build_exception
+
+    expect(`cd spec/support && bundle exec rake raise_exception 2>&1`).to match(/Sending event/)
+  end
+
+end

spec/support/Rakefile

@@ -0,0 +1,7 @@
+require 'rake'
+require 'rubygems'
+require 'raven'
+
+task :raise_exception do
+  1 / 0
+end