Adding Hash#compact and Hash#compact! methods

  * Adding Hash#compact and Hash#compact! methods
  * Using Ruby 1.9 syntax on documentation
  * Updating guides for `Hash#compact` and `Hash#compact!` methods
  * Updating CHANGELOG for ActiveSupport
  * Removing unecessary protected method and lambda for `Hash#compact` implementations
  * Performing `Hash#compact` implementation - https://gist.github.com/tinogomes/8332883
  * fixing order position
  * Fixing typo

1 files changed, 10 insertions, 0 deletions

diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
index 1a43bd206e..59dfefd22f 100644
--- a/guides/source/active_support_core_extensions.md
+++ b/guides/source/active_support_core_extensions.md
@@ -2907,6 +2907,16 @@ The method `with_indifferent_access` returns an `ActiveSupport::HashWithIndiffer
 
 NOTE: Defined in `active_support/core_ext/hash/indifferent_access.rb`.
 
+### Compacting
+
+The methods `compact` and `compact!` return a Hash without items with `nil` value. 
+
+```ruby
+{a: 1, b: 2, c: nil}.compact # => {a: 1, b: 2}
+```
+
+NOTE: Defined in `active_support/core_ext/hash/compact.rb`.
+
 Extensions to `Regexp`
 ----------------------