Heroku buildpack: Scala 
This is a Heroku buildpack for Scala apps. It uses sbt 0.11.0+.
Usage
Example usage:
$ ls
Procfile build.sbt project src
$ heroku create --buildpack https://github.com/heroku/heroku-buildpack-scala.git
$ git push heroku master
...
-----> Heroku receiving push
-----> Scala app detected
-----> Building app with sbt
-----> Running: sbt clean compile stage
The buildpack will detect your app as Scala if it has the project/build.properties and either .sbt or .scala based build config. It vendors a version of sbt and your popluated .ivy/cache into your slug. The .ivy2 directory will be cached between builds to allow for faster build times.
Hacking
To use this buildpack, fork it on Github. Push up changes to your fork, then create a test app with --buildpack <your-github-url> and push to it.
For example, to reduce your slug size by not including the .ivy2/cache, you could add the following.
for DIR in $CACHED_DIRS ; do
rm -rf $CACHE_DIR/$DIR
mkdir -p $CACHE_DIR/$DIR
cp -r $DIR/. $CACHE_DIR/$DIR
# The following 2 lines are what you would add
echo "-----> Dropping ivy cache from the slug"
rm -rf $SBT_USER_HOME/.ivy2
Note: You will need to have your build copy the necessary jars to run your application to a place that will remain included with the slug.
Commit and push the changes to your buildpack to your Github fork, then push your sample app to Heroku to test. You should see:
...
-----> Dropping ivy cache from the slug
License
Licensed under the MIT License. See LICENSE file.