Prefer %w to the literal array syntax when you need an array of strings.

https://github.com/bbatsov/ruby-style-guide#collections
Merge pull request #64 from kbighorse/master

Prefer %w to the literal array syntax when you need an array of strings.
SQL Injection teachers

[ruby regular expressions](https://github.com/bbatsov/ruby-style-guide#regular-expressions)

```ruby
string = "some injection\nusername"
string[/^username$/]   # matches
string[/\Ausername\z/] # don't match
```
Merge pull request #66 from artemeff/patch-1

SQL Injection teachers
Update starting quote
Fix validation inconsistency (fixes #67)
Fix "Rails 3 Way" url (fixes #60)
Remove bad advice on calling steps from step definitions
Merge pull request #69 from abotalov/patch-2

Remove bad advice on calling steps from step definitions
Remove invalid advice

Capybara Readme clearly says:
```
The two following statements are functionally equivalent:

page.should_not have_xpath('a')
page.should have_no_xpath('a')
```
Merge pull request #68 from abotalov/patch-1

Remove invalid advice
adding mention of "foreigner," another gem that provides foreign key enforcement at the database level
mentioning a couple often-used gemified versions of assets
Update a bit for Rails 4
Remove section on ActiveResource
Mention Sidekiq
[Fix #62] Update custom validators path
Removing client-side-validations, it is no longer maintained.
Merge pull request #70 from drewda/master

adding mention of "foreigner," another gem that provides foreign key enforcement at the database level
Merge pull request #74 from lunks/remove-cliet-side-validations

Removing client-side-validations, it is no longer maintained.