prepare for production

to use the GWT application in production you need to compile the java code to javascript. do this by

gwt compile

this will create a bunch of files in (let's say your entry point is MyApp.html)

public/MyApp

├── 0A9476898799A150D840F0B1C3672921.cache.png
├── 252E93E323E49DEBAD16801958CC7426.cache.html
├── 396F806CD63ABD414BFBB9D57429F05B.cache.png
├── 54C55E818765C1350C82B412D08B3CF3.cache.html
├── 856309C67EF69E0F3185E6194DE9C97E.cache.html
├── 933C651B88B6D25DCE690CAE14DC8393.cache.html
├── C335A03FC277D28FFC00B7892C9DBBB0.cache.html
├── C7D849B56A900BE84B51403AE9495A35.cache.html
├── CE18CF7C7088FCD25ACC685CF4BAE60B.gwt.rpc
├── clear.cache.gif
├── DF7764EEC1903CD03C9545B354D8D8E4.cache.png
├── E44767377485D18D6B6864F65BA8EF73.cache.png
├── EDC7827FEEA59EE44AD790B1C6430C45.cache.png
├── hosted.html
└── MyApp.nocache.js

there are files with a timestamp and a cached in their names. these files will get a new timestamp on each compile and can be delivered to the browser with an expires header set in future.

now everything is in place to get the code into production.

build a war file

rmvn package

will create a war inside the ./target directory.

deploy on heroku

make sure your Gemfile works for MRI as well and then bundle your MRI specific gems like this

ruby -S bundle install

where ruby is the MRI version ;-). then commit everything and push it to heroku.