Add Gemfile so that I can run the specs without installing system gems

.gitignore

@@ -3,4 +3,5 @@
 coverage
 rdoc
 pkg
-spec/credentials.yml
+spec/credentials.yml
+.bundle

Gemfile

@@ -0,0 +1,11 @@
+source 'http://gemcutter.org'
+
+gem 'rake'
+gem 'excon', '>= 0.0.21'
+gem 'excon', ">= 0.0.21"
+gem 'formatador', ">= 0.0.10"
+gem 'json', ">= 0"
+gem 'mime-types', ">= 0"
+gem 'nokogiri', ">= 0"
+gem 'ruby-hmac', ">= 0"
+gem 'rspec', '>= 0'