ruby_hook.rb

# Trigger a travis build
post "/push-webhook" do
  uri = URI.parse("https://api.travis-ci.org/repo/your-org/your-repo/requests")

  request = Net::HTTP::Get.new(uri.request_uri)
  request["Content-Type"] = "application/json"
  request["Accept"] = "application/json"
  request["Travis-API-Version"] = "3"
  request["Authorization"] = "token your-token"

  body = { "request" => { "branch" => "master" } }
  request.body = body.to_json

  response = http.request(request)
end