[aviau]

I think that is is best to open pull requests to Gitlab instead.

You may object and say that it is a bit lame to re-implement something that is already in the paid version. However, it is best than re-implementing everything from scratch.

Also, I have heard that Gitlab is open to open-sourcing features when you show interest to have it in the free version.

Take a look at this issue for example, which tracks Gnome's wishlist for Gitlab: https://gitlab.com/gitlab-org/gitlab-ce/issues/43566.

The guys behind the Gitlab company move the community edition pretty fast too, possibly faster than what we would achieve by duplicating efforts.

However, as I mentioned in another comment (https://news.ycombinator.com/item?id=17241209), this may change because the new free Ultimate/Gold subscriptions could become excuses to stop open-sourcing features to Gitlab CE.

[sytse]

We're always open to discussing open sourcing parts of GitLab. We will continue to do so on a case by case basis.