Fix .gem file permissions problem.

Tempfile.new makes files with permissions of 0600[1]. This means that if
the webserver is running as a different user, the newly uploaded .gem
file won't be readable. This patch adds a chmod to the atomicwrite
function.

1: http://www.ruby-doc.org/stdlib-1.9.3/libdoc/tempfile/rdoc/Tempfile.html#method-c-new

lib/geminabox.rb

@@ -18,6 +18,7 @@ class Geminabox < Sinatra::Base
   set :incremental_updates, false
   set :views, File.join(File.dirname(__FILE__), *%w[.. views])
   set :allow_replace, false
+  set :gem_permissions, 0644
   use Hostess
 
   class << self
@@ -215,6 +216,7 @@ def atomic_write(file_name)
     yield temp_file
     temp_file.close
     File.rename(temp_file.path, file_name)
+    File.chmod(settings.gem_permissions, file_name)
   end
 
   helpers do

test/test_support/geminabox_test_case.rb

@@ -30,6 +30,10 @@ def data(data = nil)
       @data ||= data || "/tmp/geminabox-test-data"
     end
 
+    def gem_permissions
+      0644
+    end
+
     def app(&block)
       @app = block || @app || lambda{|builder| run Geminabox }
     end
@@ -41,7 +45,9 @@ def to_app
     def should_push_gem(gemname = :example, *args)
       test("can push #{gemname}") do
         assert_can_push(gemname, *args)
-        assert File.exists?( File.join(config.data, "gems", File.basename(gem_file(gemname, *args)) ) ), "Gemfile not in data dir."
+        gem_path = File.join(config.data, "gems", File.basename(gem_file(gemname, *args)) )
+        assert File.exists?( gem_path ), "Gemfile not in data dir."
+        assert File.stat(gem_path).mode.to_s(8).match(/#{config.gem_permissions.to_s(8)}$/), "Gemfile has incorrect permissions."
       end
     end