Add application

.env

+# HTTP Basic Auth
+AUTH_USERNAME="username"
+AUTH_PASSWORD="password"
+
+# Marketo API
+MRKT_HOST=""
+MRKT_ID=""
+MRKT_SECRET=""

app.rb

+require 'json'
+
+require './lib/marketo_client'
+require './lib/user'
+
+class MarketoTools < Sinatra::Base
+  use Rack::Auth::Basic do |username, password|
+    username == ENV['AUTH_USERNAME'] && password == ENV['AUTH_PASSWORD']
+  end
+
+  # Receives GitLab System Hooks
+  #
+  # Specifically, we're interested in the `user_create` event.
+  #
+  # See http://gitlab.com/help/system_hooks/system_hooks
+  post '/' do
+    begin
+      params = JSON.parse(request.body.read)
+    rescue JSON::ParserError
+      params = {}
+    end
+
+    if params['event_name'] == 'user_create'
+      user = User.new(params)
+
+      # TODO (rspeicher): Do we need to do anything with this besides
+      # create/update a lead?
+      client.createupdate_leads([user.to_param], lookup_field: :email)
+    end
+
+    # https://dev.gitlab.org/gitlab/mailchimp-tools/commit/a93a0b97a906008e97c0fe6eccdf09ce32f944ea
+    'success'
+  end
+
+  private
+
+  def client
+    @client ||= MarketoClient.new
+  end
+end

config.ru

+require 'bundler'
+
+Bundler.require
+Dotenv.load
+
+require './app'
+run MarketoTools

lib/marketo_client.rb

+class MarketoClient < SimpleDelegator
+  attr_reader :client
+
+  def initialize
+    @client = Mrkt::Client.new(
+      host:          ENV['MRKT_HOST'],
+      client_id:     ENV['MRKT_ID'],
+      client_secret: ENV['MRKT_SECRET']
+    )
+
+    super(@client)
+  end
+end

lib/user.rb

+class User
+  include FullNameSplitter
+
+  attr_accessor :first_name, :last_name, :email
+
+  def initialize(params)
+    self.full_name = params['name']
+    self.email     = params['email']
+  end
+
+  def to_param
+    {
+      email:     email,
+      firstName: first_name,
+      lastName:  last_name
+    }
+  end
+end