Closes #20743.

The task `db:_dump` now only dumps the schema if
`ActiveRecord::Base.dump_schema_after_migration` is true. This has
effects:

- `db:migrate:up`
- `db:migrate:down`
- `db:forward`
- `db:rollback`

We recommend using the `bin/` executables in our docs and guides.
Let's make sure that our tests execute the same code path.

Improve integration_tool documentation

As per railties/lib/rails/test_unit/railtie.rb, where it sets it explicitly.

This can be confirmed by starting a new Rails console session in a new app and running this code:

Rails.application.config.app_generators.rails[:integration_tool]

I also beefed up the documentation slightly to be more explicit about what this configuration setting does.

To fix #20644

fix pluralization in doc [ci skip]

Minor addition to getting started guide for foreign_key description

Minor addition to getting started guide for foreign_key description of references migration [ci skip]

Added a note on development kit for Windows Users.  This is required as Windows users can get frustrated when their first rails project creation would fail as some native gem won't get built.

These classes are part of Active Record Preloader, which is not part of
the public API.

fix NoMethodError that occurs when generating scaffold inside full mode engine

Passing nil to image_tag

Fix cache issue when different partials use the same collection

Adds the `virtual_path` option to `cache_fragment_name` so it can
be provided when needed.

That allows `cache_collection_render` to get the appropriate cache
key with the digest generated based on the template and prevent
collision with other templates that cache the same collection.

[ci skip] Fix action_controller_overview

Closes #20705.

With this change, we will always assume the association name is the same
as the table it's referencing. This is subtly different than treating
the hash key passed to `where` as the table name, as it still allows the
class referenced by the association to provide additional type
information.

After exploring several possible solutions to the ambiguity problem, I
do not think there is a short term answer that will maintain backwards
compatibility.

This change will make it so the following code does not work:

    class User
      has_many :approved_posts, -> { where(approved: true) }, class_name: "Post"
    end

    User.where(approved_posts: { id: 1 })

But prevents potential ambiguity and collision as demonstrated in [this
gist](https://gist.github.com/senny/1ae4d8ea7b0e269ed7a0).

Unfortunately, truely solving this requires significantly
re-architecting this code, so that what is currently represented as an
`Arel::Attribute` is instead another data structure that also references
the association it is representing, so we can identify the proper table
name for aliasing when we construct the final tree.

While I'd still like to accomplish that in the long run, I don't think
I'll be able to get there in time for Rails 5 (since I'm not full time
OSS any more, and this is several weeks worth of work). I'm hoping to
achieve this for Rails 5.1.

Fixes #20308

Using `assert_predicate` and `assert_match` instead of just `assert` is
preferrable because better error messages are output.

In the case of `assert response.cookies.empty?` the error message was
`Failed assertion, no message given.` but now with `assert_predicate` it
will be `Expected {"user_name"=>"david"} to be empty?.`

For `assert_match(/user_name=david/,
response.headers["Set-Cookie"])` as well, the message returned was
unhelpful - `Failed assertion, no message given.` but now will tell what
was expected and what was returned with `Expected /user_name=david/ to
match "user_name=nope; path=/".`

Allow default_render to take a block to customize behavior when there's no template

Maintaining consistency in wording [ci skip]

"reproduce" word is better suited then "replicate" as its also used at other places in this same document having same context. It will then be consistent across document.

Remove `config` options from `default_options` in `railties`

Improve Validation Helpers' documentation comments and tests

Change documentation for collection.build and collection.create [ci-skip]

Fixes #20345.

More granular console SQL coloration

Add table name prefix and suffix support for foreign keys

Add reversible syntax for change_column_default

Change routes.rb look in getting started

correct `file_fixture_path` in plugins `test_helper.rb`

`fixture_path` does not end with a slash

Improve detection of partial templates eligible for collection caching.

Update .pluck documentation on uniq

This is to show users that they can chain `.uniq` and `.pluck` to get
the `DISTINCT column` result. They don't have to do `DISTINCT column`
themselves.