Update filter_parameters related docs, as they have been moved to initializers.
Update configuration docs for assets.enabled, as it's set true by default in the configuration and doesn't appear in the config files anymore.
update_counters accepts a hash, not an array of hashes
Documentation: Notifications queue does not run in a thread.
In rails 4 there are much more ways to retrieve a single object
Added an example for primary_key option
enhanced comments for foreign_key_present? method
correction on cache.fetch race_condition_ttl
Merge pull request #138 from lifo/cache

correction on cache.fetch race_condition_ttl
Correct the assertion that join table columns have no options, mind context.
removes forgotten avatar
minor comments cleanup
Fixed quotes in environment example in Rails Application Templates guide.
End-of-line whitespace hunt
Consistent use of one space only after punctuation
Remove double spaces in code examples
Remove double spaces in guides
Remove references to deprecated test tasks
Consistent one-spaced bullets in guides release notes
Whitespace trimming in guides generation