[WIP] Bootstrap v4

[mattbrictson]

This is our official PR that consolidates all changes needed to support Bootstrap v4.

This PR is a work in progress. It may or may not be merged, depending on whether we decide to publish this as a separate version or even spin it off as a separate gem. If you have ideas or feedback on these logistical topics, please join the discussion here: #268

If you would like to try this preliminary Bootstrap v4 support in your Rails project, use the following Gemfile entry:

gem "bootstrap_form", git: "https://github.com/bootstrap-ruby/rails-bootstrap-forms.git", branch: "bootstrap-v4"

If you would like to contribute to this branch (i.e. fix bugs or provide wrappers for additional v4 features), please open your own PR and use rails-bootstrap-forms:bootstrap-v4 as the base branch. If and when your PR is reviewed and merged, it will become part of this larger PR.

Thanks for your help!

[GBH]

This PR probably should be closed as it's not correct for Boostrap4 beta3

• has_danger is not a thing: https://getbootstrap.com/docs/4.0/components/forms/#server-side
• form-control-feedback not a thing either. It's invalid-feedback
• form-control-label not a thing. col-form-label is used for horizontal forms though: https://getbootstrap.com/docs/4.0/components/forms/#horizontal-form

Let's close this and promote bootstrap-v4 to master so we can start working on it.

[mattbrictson]

@GBH good finds. Should we still merge this branch into master as originally planned, and then address these issues from there?

[mattbrictson]

Rebased against latest master

[GBH]

@mattbrictson I think it's fine to merge. Let's just promote everything v4 to master so new PRs can be made.

[mattbrictson]

@GBH great, thanks! 👍

@lcreid, @donv, @desheikh: any concerns before I merge this?

[lcreid]

I (and I'm sure many other people) have been using the bootstrap-4 branch for some time. We should merge this and fix up the small differences between Bootstrap 4 when this PR was done, and Bootstrap 4 as it is now (e.g. has-danger).

[lcreid]

As @GBH pointed out, has-danger isn't in Bootstrap 4 anymore. We should either fix the PR, or merge and remember to fix. Whatever is easier.

[GBH]

I vote for merge and fix later or this is going to be sitting here for weeks.

[lcreid]

TODO: Fix this class. I think we want is-invalid now, but correct me if I'm wrong.

[mattbrictson]

Thanks @lcreid, I added a reminder to #361 to deal with has_danger, form-control-feedback, and form-control-label. I'll merge this now.