Notify Sentry of a new release via Capistrano

deploy.rb

# This task will notify Sentry via their API[1] that you have deployed
# a new release. It uses the release timestamp as the `version`
# (like 20151113182847) and the git ref as the optional `ref` value.
#
# This task requires several environment variables be set (or just 
# hardcode the values in here if you like living on the edge):
#
#   ENV['SENTRY_API_ENDPOINT'] : API endpoint, https://app.getsentry.com
#   ENV['SENTRY_ORG']          : the organization for this app
#   ENV['SENTRY_PROJECT']      : the project for this app
#   ENV['SENTRY_API_KEY']      : your API key (not DSN) [2]
#
# [1]: https://docs.getsentry.com/hosted/api/releases/post-project-releases
# [2]: https://app.getsentry.com/organizations/YOUR-ORG-SLUG/api-keys

# For Rails app, this goes in config/deploy.rb

namespace :sentry do
  task :notify_deployment do
    run_locally do
      require 'uri'
      require 'net/https'

      puts "Notifying Sentry of release..."
      uri = URI.parse(ENV['SENTRY_API_ENDPOINT'])
      http = Net::HTTP.new(uri.host, uri.port)
      http.use_ssl = true

      req = Net::HTTP::Post.new("/api/0/projects/#{ENV['SENTRY_ORG']}/#{ENV['SENTRY_PROJECT']}/releases/", initheader={'Content-Type' =>'application/json'})
      req.basic_auth(ENV['SENTRY_API_KEY'], '')
      req.body = %Q[{"version":"#{fetch(:release_timestamp)}","ref":"#{fetch(:current_revision)}"}]

      response = http.start { |h| h.request(req) }
      puts "Sentry response: #{response.body}"
    end
  end
end

# If you want deployments to be published in every Rails environment, put this
# in config/deploy.rb, otherwise put it your environment-specific deploy file
# i.e. config/deploy/production.rb

after 'deploy:published', 'sentry:notify_deployment'

thanks @cannikin, a fork with auth token (instead of api key) can be found here https://gist.github.com/pablopaul/892d7f8b3f031985f1c690cbeff9ef9e