add config endpoint

lib/travis/api/app/endpoint/home.rb

@@ -3,7 +3,12 @@ require 'travis/api/app'
 class Travis::Api::App
   class Endpoint
     class Home < Endpoint
-      set(:prefix, '/')
+      set :prefix, '/'
+      set :client_config,
+        host: Travis.config.host,
+        shorten_host: Travis.config.shorten_host,
+        assets: Travis.config.assets,
+        pusher: { key: Travis.config.pusher.try(:key) }
 
       # Landing point. Redirects web browsers to [API documentation](#/docs/).
       get '/' do
@@ -22,6 +27,24 @@ class Travis::Api::App
         halt 400 unless params[:to] =~ %r{^https?://}
         redirect params[:to]
       end
+
+      # Provides you with system info:
+      #
+      #     {
+      #       config: {
+      #         host: "travis-ci.org",
+      #         shorten_host: "trvs.io",
+      #         pusher: { key: "dd3f11c013317df48b50" },
+      #         assets: {
+      #           host: "localhost:3000",
+      #           version: "asset-id",
+      #           interval: 15
+      #         }
+      #       }
+      #     }
+      get '/config' do
+        { config: settings.client_config }
+      end
     end
   end
 end