Fix Request#params on PUT requests [#72]

Works around an issue introduced in Rack 0.9.0 with
request body params not being parsed when the request method
is PUT. This should be reverted once a fix lands in Rack.

Ticket for Rack fix:
http://rack.lighthouseapp.com/projects/22435-rack/tickets/20

More:
http://sinatra.lighthouseapp.com/projects/9779/tickets/72

lib/sinatra/base.rb

@@ -14,6 +14,13 @@ module Sinatra
     def accept
       @env['HTTP_ACCEPT'].split(',').map { |a| a.strip }
     end
+
+    # Override Rack 0.9.x's #params implementation (see #72 in lighthouse)
+    def params
+      self.GET.update(self.POST)
+    rescue EOFError => boom
+      self.GET
+    end
   end
 
   class Response < Rack::Response

test/request_test.rb

@@ -6,4 +6,13 @@ describe 'Sinatra::Request' do
     assert request.respond_to?(:user_agent)
     assert_equal 'Test', request.user_agent
   end
+
+  it 'parses POST params when Content-Type is form-dataish' do
+    request = Sinatra::Request.new(
+      'REQUEST_METHOD' => 'PUT',
+      'CONTENT_TYPE' => 'application/x-www-form-urlencoded',
+      'rack.input' => StringIO.new('foo=bar')
+    )
+    assert_equal 'bar', request.params['foo']
+  end
 end