make the warning clear about the effect of using validates_associated on both sides on an association.

Simple_format should not edit it in place. (Fixes https://github.com/rails/rails/issues/1980)

ActionView::Helpers::TextHelper#simple_format should not change the text in place. Now it duplicates it.

fix stringify_keys destructive behavior for most FormTagHelper functions

add four new tests to verify that the other three methods that called stringify_keys! are fixed. verified that the tests break in master without the code patch. Closes #2355

Quote these dates to prevent intermittent test failure. Suppose local time is 00:50 GMT+1. Without the quoting, the YAML parser would parse this as 00:50 UTC, into the local time of 01:50 GMT+1. Then, it would get written into the database in local time as 01:50. When it came back out the UTC date from the database and the UTC date of two weeks ago would be compared. The former would be 23:50, and the latter would be 00:50, so the two dates would differ, causing the assertion to fail. Quoting it prevents the YAML parser from getting involved.

accept hash of options to recreate database for postgres adapter

Don't require assets group in production by default, you can change this default in the application.rb anyways