Add automatic deployment preview of PRs when changing the site

[jkremser]

This is basically #657 + #658 combined to just one (no need to have a makefile target on the gh-pages branch if it's done in the bash script)

Signed-off-by: Jirka Kremser jiri.kremser@gmail.com

[somaritane]

@jkremser, it would have been better to just leave #658 open and not create a new PR in order to keep the context.

[ytsarev]

can it also run make target so we can put contents of .netlifty.sh into the Makefile?

[jkremser]

Half of them yes, but these:

    if ! git config remote.origin.url &> /dev/null; then
        git remote add -f -t gh-pages origin https://github.com/k8gb-io/k8gb
    fi
    git fetch origin gh-pages:gh-pages
    git checkout gh-pages

must be done on the ref representing the PR which is checked out by default. If I split the commands into those that must be present in the netlify.toml on a pr branch and those that can be stored in the gh-pages' Makefile, I'd end up basically w/ the two original PRs, lol

[ytsarev]

Original PR was using Makefile on gh-pages, meanwhile I suggest to use standard Makefile at https://github.com/k8gb-io/k8gb/blob/master/Makefile

[jkremser]

got ya, yes, Netlify env. can run make targets... if we put the content of the bash script to the main Makefile (that 1 on the master's branch), that should work

[jkremser]

done using the Makefile target @ master