Guideline: Add bundler/spring binstubs to version control

* Make sure each member of a team has access to binstubs
* Syncronize what the stub uses (Bundler, Rails, or Spring)
* Allow just one project PATH entry

The rbenv wiki has an excellent guide on binstubs:

https://github.com/sstephenson/rbenv/wiki/Understanding-binstubs
Prefer have_css to have_selector with RSpec + Capybara

While have_selector supports CSS selectors and XPath selectors, have_css
is most often how we assert elements are present in the DOM; as an added
benefit, it's shorter to type.
Specify method chaining dot style rule

When splitting up a chain of method calls, use a trailing `.` and place each
method on its own line
```ruby
foo.
  bar.
  baz
```
change newline to emtpy line
Add migration styles

* Default non-presence-validated string fields to empty string to avoid nil values
* Put timestamps at the top when creating a table for consistency
Force push rebased feature branches before merging
Add note about Hound automatically reviewing style
Prefer `==` to `is` in CoffeeScript

Given that we prefer things like `&&` to `and` in ruby and other
languages, it'd be nice to be consistent about this in CoffeeScript as
well. I also find code that uses `is`, `isnt`, `and`, and `or` to be
signficantly less readable.
Preliminary Haskell style guide and best practices
Rule for trailing commas in multi-line lists

Without a trailing comma on the last item in a list, adding a new item causes a
deletion and two insertion in Git diffs.

With a trailing comma on the last item in a list, adding a new item causes only
one insertion and no deletions.
Clarify guideline on the use of boolean operators

The use of the term 'boolean expression' left some uncertainty as to
when to use which operators. See
https://github.com/thoughtbot/whetstone/pull/30#discussion_r10706657