Fix installable, and make sure we run `rum requirements`.
Add $HOME/.rbenv to $PATH even if it's installed
Remove rbenv-gem-rehash plugin installation

This plugin was merged into rbenv
https://github.com/sstephenson/rbenv/pull/638
Remove redundant Foreman

It is installed earlier via https://toolbelt.heroku.com/
Remove Heroku Config

I haven't been using `heroku config:pull`, etc. for some time.
Instead, I've been using more targeted shell lines insides our
[`bin/setup`] convention, such as:

    if ! grep -F "FILEPICKER" .env > /dev/null; then
      heroku config --remote staging | grep "FILEPICKER" >> .env
      sed -i '' 's/\:/=/' .env
      sed -i '' 's/ //g' .env
    fi

[`bin/setup`]: http://robots.thoughtbot.com/bin-setup

This is more targeted and automated than using `heroku config:pull`.
Use Homebrew for rbenv and ruby-build

* Many thoughtbot employees are successfully using Homebrew'd rbenv.
* rbenv's recommended install is Homebrew for OS X:
  https://github.com/rbenv/rbenv#installation
* We use Homebrew / package management whenever possible for
  system dependencies.
* We save a step adding rbenv to `PATH` in zshrc / zshenv,
  because Homebrew does it for us.
  This is nice because we don't add `rbenv` to `PATH` in
  thoughtbot/dotfiles.
Use ShellCheck to enforce shell style

* Document in "Contributing" section.
* Use GitHub code fences to improve syntax highlighting.
* Don't be so Rails-y in the documentation.
Suggested installation includes an explicit review step

While we did previously state "Read, then...", that's easier to ignore.
This brings the copy-pastable commands in line with the intent: to have
the user review the script before executing it. This also removes the
potentially confusing use of process substitution.

Note: The presence of `less` is assumed to avoid assumptions about
editors or the noise of handling that robustly (e.g. `${EDITOR:-vim}`)
Install libyaml to avoid failed Ruby compilation

I saw this problem while installing Ruby 2.1.4.
Installing libyaml first solved the problem.

https://github.com/sstephenson/ruby-build/wiki#suggested-build-environment
Rehash to get `bundle` command
Remove Parity, Watch, Suspenders, and Rails

* These are great tools, but not critical.
* Some tools should be re-installed right before their use,
  such as Suspenders.
* Restrict Laptop to more fundamental setup.
* Document how to install these in `~/.laptop.local`.
Document that we install (or update) RCM
Use `tree` as customization example

Laptop should be responsible for setting up
the compilers,
system package manager,
programming language version managers & installers,
large system dependencies such as Postgres,
and any critical config for those tools
which is often overlooked but can cause bugs and headaches.

Other useful command-line tools such as `watch` and `tree`
are better installed in individuals' `~/.laptop.local` files.

Add `tree` as a good example for that file.

Try to make `~/.laptop.local` explanation clearer
and more prominent by placing it in a heading.

Remove Suspenders as an example.
Right before using Suspenders,
it's probably best to re-install it to get the latest.
Be more specific in printed output

* Say whether we are Installing, Upgrading, or Skipping.
* Changes the behavior of `brew_install_or_upgrade`
  but simplifies and shortens the rest of the script.
Use Homebrew for Git

We previously relied on the version of Git
that comes with Xcode.
The Homebrew version is easier to upgrade
when new versions of Git are released,
such as yesterday's security patch:

https://github.com/blog/1938-git-client-vulnerability-announced
Use rbenv shell instead of rbenv local

`rbenv local` creates a `.ruby_version` file
in the current directory.
Install, upgrade, or skip Bundler
Add gem_install_or_update function

* Use it for Bundler.
* Document it for others' use in their ~/laptop.local.
* Delete out of date part of README.
Put freetds back in.
Merge branch 'umaster'

Conflicts:
	README.md
	mac