It is too hard to run travis on forked repositories.
It disturbs pull request process.

Travis does not run Pull Request for Pull Request.
https://github.com/opf/openproject/pull/1392

For keeping clean revision history.
https://github.com/opf/openproject/pull/1338#issuecomment-44260428

OpenProject members break their rules.
https://www.openproject.org/projects/openproject/wiki/Git_Workflow
> Fork Openproject on GitHub

DVCS standard rule save much time.
https://help.github.com/articles/fork-a-repo

OpenProject stupid *undocumented* rule.
http://marutosi.bitbucket.org/RxTstudy-20130622/one-html/html/index.html#id236

DVCS standard rule.
http://marutosi.bitbucket.org/RxTstudy-20130622/one-html/html/index.html#id236

https://github.com/opf/openproject/pull/1362
https://github.com/rails/rails/blob/2367dfeb8d7c4596263e/.travis.yml