failure to parse params should trigger a 400 Bad Request
Improve poor security recommendation in docs

As reported in #9960, the current documentation recommends an insecure practice for
key generation from a password (a single round of SHA-256). The modified documentation
uses ActiveSupport::KeyGenerator to perform proper key stretching.
Fixes skipping object callback filters

This allows you to skip callbacks that are defined by objects, e.g. for
`ActionController`:

    skip_after_filter MySpecialFilter

Previously this didn't work due to a bug in how Rails compared callbacks
in `Callback#matches?`. When a callback is compiled, if it's an object
filter (i.e. not a method, proc, etc.), `Callback` now defines a method on
`@klass` that is derived from the class name rather than `@callback_id`.
So, when `skip_callback` tries to find the appropriate callback to
remove, `Callback` can regenerate the method name for the filter
object and return the correct value for `Callback#matches?`.
Fix loading of string arrays in postgres
options_from_collection_for_select helper takes html attributes

as the last element of the array
Use strip_heredoc where possible

Following up on an observation by @rafaelfranca

https://github.com/rails/rails/pull/10170/files#r3753963

Reduce the number of gsub calls to the two cases where inputs are concatenated
from various sources and with inconsistent indentation.

Also zap extraneous spacing from the sass-rails line... presumably this is a
holdover from a previous time where this aligned the version string with an
adjacent line.
added a test suite for the postgres binary type
this shows a problem with nil values
fix for the bytea/binary nil value bug
Document collection.create! on has_many associations in ActiveRecord
Merge pull request #10212 from mariovisic/active_record_doc

Add documentation for `collection.create!` on has_many records. [ci skip]
interpolate instead of string concat
Merge pull request #10220 from vipulnsward/interpolate_on_string

interpolate instead of string concat
Merge pull request #10214 from mattetti/ar_postgres_bytea

AR postgres binary bug fix
Merge pull request #10178 from rubys/app_base_strip_heredoc

Use strip_heredoc where possible
Revert "fixing bit string test"

This reverts commit cdd293cb963b895ff580eb20d10f5d56ecb3d447.

Reason: This wasn't properly fix.
Add OID::Bit for supporting bit string.
Merge pull request #10225 from kennyj/fix_bit_string_problem

Fix bit string problem
make [] method in router more readable
Merge pull request #10226 from buddhamagnet/master

Make [] method more readable
Fix freeze applying to cloned objects

Previously, freezing a cloned ActiveRecord object froze the original
too. By cloning `@attributes` before freezing, we prevent cloned objects
(which in Ruby share state of ivars) from being effected by `#freeze`.

Resolves issue #4936, which has further information on this issue, as
well as steps to reproduce.

* Add a test case for `#freeze` not causing `cloned.frozen?` to be true.
* Clone @attributes before freezing in `ActiveRecord::Core`, then
  reassign the cloned, frozen hash to the frozen model's `@attributes`
  ivar.

/cc @steveklabnik