Add case guideline for SQL key words, identifiers

The intent of uppercasing SQL key words and lowercasing SQL identifiers
is to distinguish them from each other, separating SQL names from the
domain names (table and column names).

http://www.postgresql.org/docs/9.2/static/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS

Also, fix alphabetical sorting of 'Formatting' section.
Update copyright year to 2013
[style] Use Newlines around multi-line blocks
Add Code Review guide

Asychronous code review via Github pull requests can be incredibly
efficient, but easy to accidentally offend or miscommunicate if we
aren't careful about our language choices or have a common expectation
of how to act when reviewing and responding to reviews.

This new guide attempts to set some basic expectations to streamline
code reviews and help us stay happy, healthy, and working closely as a
team.

* Distinguish between discussions that are appropriate for code reviews
  versus those that are appropriate for technique discussions.
* Include simplicity as a goal.
* Summarize offline conversation.
* Show, not tell, how to link to project management system ticket.
* Clarify sign off.
Use more gender-neutral adjective

https://github.com/thoughtbot/guides/pull/47
Use ./bin/setup convention in protocol guide
Add project management link to commit message

* Create a connection between project management system and git history.
* Make it easy for future developers to understand the reasons why code
  exists without having to disturb the original author or relying on the
  original author being available/on the project/not sick/not on
  vacation/ with the company at a later date.
* It requires little effort (10-20 seconds) to add the link.
* It encourages a ticket/story for commits.

https://github.com/thoughtbot/guides/pull/40
Ruby guideline: avoid explicit return statements

* Having more than one exit path in a method is confusing
* Explicit return at the end of a method is unnecessarily noisy
Add liftoff to iOS setup instructions
Introduce example of code surrounding multi-line blocks

* Adds example of code that requires extra blank line

https://github.com/thoughtbot/guides/pull/41
Add Python style guide.
Change links' paths to relative

Since GitHub introduced [relative links in markup
files](https://github.com/blog/1395-relative-links-in-markup-files),
links with absolute paths such as
`/thoughtbot/guides/blob/master/...` will no longer work.
Add Sass style guide
Add product management process with Trello

Eventually have similar documents for Trajectory, Pivotal Tracker.
Avoid organizational comments

* Based on summary from technical research card.
Add best practices for Ruby gems

Content is from old thoughtbot development handbook.
Avoid bypassing Rails validations

Extracted from old thoughtbot development handbook.
Add date/datetime column suffixes to style guide

Extracted from old thoughtbot development handbook.
Create Ruby on Rails section of code review

Extracted from old thoughtbot development handbook.
Clean up Bundler guidelines

* Remove old Bundler recommendation in Rails section, which has been
  superceded by the Bundler section.
* Alphabetize Bundler guidelines.
* Wrap at 80 characters where possible.
* Fix URL to `ruby` directive in `Gemfile` docs.