Added test to ensure that DescendantsTracker does not leak memory on singleton classes
DirtyModel uses a hash to keep track of any changes made to attributes
of an instance. When using the attribute_will_change! method, you must
supply a string and not a symbol or the *_changed? method will break
(because it is looking for the attribute name as a string in the keys
of the underlying hash). To remedy this, I simply made the underlying
hash a HashWithIndifferentAccess so it won't matter if you supply
the attribute name as a symbol or string to attribute_will_change!.
make sure both headers are set before checking for ip spoofing
Fix doc in Postgres database creation
add active model basics wip to guides/documents.yaml
Remove sqlite specific`supports_autoincrement?` which always defaults to true
support :unless_exist for FileCache
"generates" applies to "collection radio" so it should be singular
take out reference to previous versions of Rails
Revert ""generates" applies to "collection radio" so it should be singular"

This reverts commit faeb33dc036e4f707491c91a23ee3e990573141b.

Reason: Code changes can't be done on docrails
Updated with latest method [ci skip]
Updated the file path [ci skip]
Updated guides with latest method [ci skip]
Removed doc of diff method [ci skip]
asset_url => asset-url in sass-rails docs [ci skip]
EncryptedCookieStore => CookieStore [ci skip]
surplus : in attachment_fu plugin

surplus ':' character in url
incorrect urls 

I've found two incorrects urls for adding ':' at the end of the url
incorrect url

incorrect url
Fix Show link on resource