Accept and pass :credential_provider option to AWS-SDK

lib/paperclip/storage/s3.rb

@@ -212,7 +212,7 @@ module Paperclip
             config[:proxy_uri] = URI::HTTP.build(proxy_opts)
           end
 
-          [:access_key_id, :secret_access_key].each do |opt|
+          [:access_key_id, :secret_access_key, :credential_provider].each do |opt|
             config[opt] = s3_credentials[opt] if s3_credentials[opt]
           end
 

test/storage/s3_test.rb

@@ -720,6 +720,23 @@ class S3Test < Test::Unit::TestCase
     end
   end
 
+  context "An attachment with S3 storage and S3 credentials with a :credential_provider" do
+    setup do
+      class DummyCredentialProvider; end
+
+      rebuild_model :storage => :s3,
+                    :bucket => "testing",
+                    :s3_credentials => {
+                      :credential_provider => DummyCredentialProvider.new
+                    }
+      @dummy = Dummy.new
+    end
+
+    should "set the credential-provider" do
+      assert_kind_of DummyCredentialProvider, @dummy.avatar.s3_bucket.config.credential_provider
+    end
+  end
+
   context "An attachment with S3 storage and specific s3 headers set" do
     setup do
       rebuild_model :storage => :s3,