Serve assets from s3 bucket in Rails 4.2.1 - css

Question

I am just wondering if the configuration setup has changed at all (since Rails 4) with regards to setting up asset_sync and serving my assets from an s3 bucket.
I cannot seem to be able to serve my css or js assets (though images, jpg, png) are ok. I can upload everything to my s3 bucket.
I am trying to get this to work in my development environment before I push to production.
So my asset_sync.rb initializer is setup like so
if defined?(AssetSync)
AssetSync.configure do |config|
config.fog_provider = 'AWS'
config.aws_access_key_id = ENV['AWS_ACCESS_KEY_ID']
config.aws_secret_access_key = ENV['AWS_SECRET_ACCESS_KEY']
config.fog_directory = ENV['FOG_DIRECTORY']
config.existing_remote_files = "delete"
config.gzip_compression = true
config.manifest = true
config.custom_headers = { '.*' => { cache_control: 'max-age=315576000', expires: 1.year.from_now.httpdate } }
end
end
So I know that this part is ok as assets are uploaded to the bucket, but when I try and render my page no css/js or image are shown. I have set this in my development.rb
config.action_controller.asset_host = "https://#{ENV['FOG_DIRECTORY']}.s3.amazonaws.com"
All I get back at the moment on each asset is a 403 forbidden error.
This is my IAM policy, maybe someone could spot something in here that isn't correct?
{
"Version": "2012-10-17",
"Statement": [
{
"Action": [
"s3:ListAllMyBuckets",
"s3:GetObject"
],
"Effect": "Allow",
"Resource": "arn:aws:s3:::*"
},
{
"Action": "s3:*",
"Effect": "Allow",
"Resource": "arn:aws:s3:::mybucket"
},
{
"Action": "s3:*",
"Effect": "Allow",
"Resource": "arn:aws:s3:::mybucket/*"
}
]
}
I have also added a bucket policy
{
"Version":"2012-10-17",
"Statement":[
{
"Sid":"AddPerm",
"Effect":"Allow",
"Principal": "*",
"Action":["s3:GetObject"],
"Resource":["arn:aws:s3:::mybucket/*"]
}
]
}
What I am looking for is for someone to show how they setup their Rails app with asset_sync please to see if I have missed anything.