Fix content type being reset when using file cache storage

lib/carrierwave/sanitized_file.rb

@@ -186,9 +186,9 @@ def move_to(new_path, permissions=nil, directory_permissions=nil, keep_filename=
       move!(new_path)
       chmod!(new_path, permissions)
       if keep_filename
-        self.file = {:tempfile => new_path, :filename => original_filename}
+        self.file = {:tempfile => new_path, :filename => original_filename, :content_type => content_type}
       else
-        self.file = new_path
+        self.file = {:tempfile => new_path, :content_type => content_type}
       end
       self
     end

spec/sanitized_file_spec.rb

@@ -307,6 +307,13 @@
       it "should return itself" do
         expect(sanitized_file.move_to(file_path("gurr.png"))).to eq(sanitized_file)
       end
+
+      it "should preserve the file's content type" do
+        content_type = sanitized_file.content_type
+        sanitized_file.move_to(file_path("new_dir","gurr.png"))
+
+        expect(sanitized_file.content_type).to eq(content_type)
+      end
     end
 
     describe "#copy_to" do

spec/storage/fog_helper.rb

@@ -64,8 +64,8 @@ class FogSpec#{fog_credentials[:provider]}Uploader < CarrierWave::Uploader::Base
         end
 
         it "should have a content_type" do
-          expect(@fog_file.content_type).to eq('image/jpeg')
-          expect(@directory.files.get(store_path).content_type).to eq('image/jpeg')
+          expect(@fog_file.content_type).to eq(file.content_type)
+          expect(@directory.files.get(store_path).content_type).to eq(file.content_type)
         end
 
         it "should have an extension" do
@@ -244,6 +244,10 @@ class FogSpec#{fog_credentials[:provider]}Uploader < CarrierWave::Uploader::Base
         it "should upload the file", focus: true do
           expect(@directory.files.get('uploads/tmp/test+.jpg').body).to eq('this is stuff')
         end
+
+        it 'should preserve content type' do
+          expect(@fog_file.content_type).to eq(file.content_type)
+        end
       end
 
       describe '#retrieve_from_cache!' do
@@ -415,6 +419,16 @@ class FogSpec#{fog_credentials[:provider]}Uploader < CarrierWave::Uploader::Base
 
     end
 
+    describe "with a valid File object with an explicit content type" do
+      let(:file) do
+        CarrierWave::SanitizedFile.new(stub_file('test.jpg', 'image/jpeg')).tap do |f|
+          f.content_type = 'image/jpg'
+        end
+      end
+
+      it_should_behave_like "#{fog_credentials[:provider]} storage"
+    end
+
     describe "with a valid path" do
       let(:file) do
         CarrierWave::SanitizedFile.new(file_path('test.jpg'))