The PR #13767 added link to the upgrading guide to explain
details about activerecord_deprecated-finders. However the link target
features a stack of changes not releated at all. Also the relevant details
are not very informative.

I think we better link to the README so people can see what the gem is about
and how to use it.

/cc @chancancode @zzak

The file is config/secrets.yml, not config/initializers/secrets.yml.

Add link to upgrade guide for full list of deprecated finders [ci skip]

Fix a typo that says you application [ci skip]

Fix for incorrect link that is pointing to Rails blog [ci skip]

Update Error Message when secrets.secret_key_base isn't given

set encoding for pipe to binary mode

Update Changelog, Spring is under rails/spring [ci skip]

Spring in now under rails/spring [ci skip]

spring gem moved to rails/spring

Restore ActiveRecord states after a rollback for models w/o callbacks

This fixes a regression (#13744) that was caused by 67d8bb96.

In 67d8bb96, we introduced lazy rollback for records, such that the
record's internal states and attributes are not restored immediately
after a transaction rollback, but deferred until they are first
accessed.

This optimization is only performed when the model does not have any
transactional callbacks (e.g. `after_commit` and `after_create`).

Unfortunately, the models used to test the affected codepaths all
comes with some sort of transactional callbacks. Therefore this
codepath remains largely untested until now and as a result there are
a few issues in the implementation that remains hidden until now.

First, the `sync_with_transaction_state` (or more accurately,
`update_attributes_from_transaction_state`) would perform the
synchronization prematurely before a transaction is finalized (i.e.
comitted or rolled back). As a result, when the actuall rollback
happens, the record will incorrectly assumes that its internal states
match the transaction state, and neglect to perform the restore.

Second, `update_attributes_from_transaction_state` calls `committed!`
in some cases. This in turns checks for the `destroyed?` state which
also requires synchronization with the transaction stae, which causes
an infnite recurrsion.

This fix works by deferring the synchronization until the transaction
has been finalized (addressing the first point), and also unrolled
the `committed!` and `rolledback!` logic in-place (addressing the
second point).

It should be noted that the primary purpose of the `committed!` and
`rolledback!` methods are to trigger the relevant transactional
callbacks. Since this code path is only entered when there are no
transactional callbacks on the model, this shouldn't be necessary. By
unrolling the method calls, the intention here (to restore the states
when necessary) becomes more clear.

Correct the version number to 4 in guides[ci skip]

find_by_* and find_by_*! are not deprecated for example, so lets add a
note only where it is needed

[ci skip]

clean up security guide: his => their [ci skip]

Improve ERB dependency detection

Just create a local variable whenever we need the record, rather than
doing an extra find for every test on the setup method.