You can use the standard Heroku Java buildpack to compile your WAR file, and then have Wildfly run it:
$ heroku buildpacks:clear $ heroku buildpacks:add heroku/java $ heroku buildpacks:add https://github.com/jkutner/heroku-buildpack-wildfly
Then deploy your Maven project with a
pom.xml, Heroku will run the Java buildpack to compile it, and as long as you output a
target/*.war file the Wildfly buildpack will run it.
Copy the snippet above into CLI.