I have GitHub integration and Scala plugin enabled on my Intellij Ultimate. All I want to do is to create a Scala project and be able to publish it on to GitHub so that my collaborators can check out the project using their Intellij (with the same config as mine). I do the following steps. What am I doing wrong?
I would not check-in IntelliJ specific (or eclipse specific) files at all, why limit the contributors to a specific IDE? and why limit them to specific settings? I think you have 2 main choices that will allow any collaborator to work on the project while making the configuration overhead of a new contributor to a minimum.
Maven - although for Scala projects sbt is more idiomatic, maven is ubiquitous, supported by all major IDEs - and doens't even require to have an IDE
SBT - although it has less "mainstream" support in IDEs it can create the project files for you using plugins (e.g. see this question: How to create SBT project with IntelliJ Idea?)
I would recommend #1 - start with a new Maven project, and add a Scala nature, you can create it from an archtype so scala compilation is supported from maven command line (see this for example)