Travis-CI for mdbook and gh-pages

[milesfrain]

Here is an example of the Travis job running on my travis-demo branch.

Preview: https://milesfrain.github.io/purescript-book/

The only difference with this PR is the removal these lines to default to master branch:

  on:
    branch: travis-demo # Will default to master branch if on.branch is removed

The remaining configuration steps are:

• Activate travis on this repo. Edit: Already running on travis-ci.com (previously liked to inactive travis-ci.org instance ... confusing).
• Generate and add github token to Travis repo.
• Whatever else might be needed for compatibility with a custom domain name: book.purescript.org

@hdgarrood we could use your help with these administrative tasks.

[hdgarrood]

Can I request that we use dplv2 with a deploy key? That way if the key does get compromised somehow it will only be able to modify this repository, whereas if a personal access token is compromised then the attacker would be able to modify any repository the owner of the token has access to.

[milesfrain]

Can I request that we use dplv2 with a deploy key?

Sounds good. Updated PR

[hdgarrood]

I guess we (I) will need to change the github pages configuration for this repo so that it uses the gh-pages branch for the site rather than the master branch, as it does currently. I'll do that once this PR is merged and the auto deployment has successfully built the book and pushed it to the gh-pages branch.

[milesfrain]

@hdgarrood Looks like there was an issue with the deploy key.
https://travis-ci.com/github/purescript-contrib/purescript-book/builds/160480788
I don't have access to the repository settings, so it's tough for me to troubleshoot.

[hdgarrood]

I've fixed it - apparently the deploy_key option needs to point to a file which contains the key, you can't just put the key in the environment variable directly. I followed Travis' guide to adding encrypted files and added deploy_key.enc to the repo. This now seems to be working, but the book.purescript.org link is no longer working because the CNAME file doesn't appear to have made it across into the gh-pages branch.

[milesfrain]

the CNAME file doesn't appear to have made it across into the gh-pages branch

Did a quick commit (or two) to fix this.
Looks like it's working now.

[hdgarrood]

Oh, I've just spotted that the README is no longer present in the rendered HTML - can we configure mdbook to include it?

[milesfrain]

Fixed with #86