There is no Debian repository for fluentd, only for Ubuntu. We will install the package from git using ruby.
apt-get install git ruby ruby-dev make
gem install bundler
git clone https://github.com/fluent/fluentd.git
cd fluentd/
bundle install
bundle exec rake build
gem install pkg/fluentd-0.10.52.gem
curl -L http://toolbelt.treasuredata.com/sh/install-redhat.sh | sh