My company has open sourced a lot of code (80% of our products) and finding people outside willing to contribute is actually quite difficult if you don't do things properly. We actually spent quite some time to improve the build and the branding, to check the intellectual property of our dependencies etc.
If you want real contributors, building a community often require a good documentation, examples, etc.
If you want real contributors, building a community often require a good documentation, examples, etc.