Ask HN: How do your team write documentation?

Hello,

I have got questions regarding documentation writing within a team of software engineers.

Some context:

I am a new project leader in the computing department of a medium-sized company. My team is 6 software engineers. We are building a new product, and I cannot get the team to write documentation - we need both an user guide and API documentation too. It is seriously lagging behind, for 3 main reasons I guess:

* the product is a moving target, API is not 100% stable, no one wants to start something and have to redo it later

* everybody in the team prefers to write new features and code than documentation

* the release date seems "far away" (in 18 months)

We follow a kind of scrum methodology, but it is not enough to have documentation stories to get nice documentation ;)

So here are my questions:

* how do you deal with developers writing documentation ?

* are there some techniques that help ?

* which tools do you use ? I am thinking of gitbook for user guide, and Sphynx for API documentation

* is it a good idea to hire a "technical writer" to have a specialist writing documentation instead of software engineers ?

* how does it work for open-source projects ? Documentation is sometimes really great, I would like to know the recipe :)

Any help would be appreciated !

Thanks in advance.