* Strips leading underscores.
* Changes some unnecessary gsub!s to sub!s.
* Replaces some anchors ^, $ with \A, \z.
* Documents that human inflection rules are applied.
* Documents that words are downcased except acronyms.
* Adds an example with an acronym.
* Rewords docs.

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on the Getting Started guide.

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Added 2 changes suggested by @robin850 [skip ci]

Let's tell people that they should rely on Tokaido instead of Rails One
Click.

Fixes #14960.

This reverts commit fe985960, reversing
changes made to add95606.

Benefits: https://creativecommons.org/version4

This commit adds new lines between titles, paragraphs and code blocks
for an easier reading.

Moreover, in order to be consistent with the other guides, let's remove
the sharps on the right side of the different titles.

The "Running a Single Test" part was also explained after the "Testing
Active Record" one which shows how to run a single test under the scope
of a specific adapter.

Finally, let's explain the `-n` option to run a specific test method.

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Update the Getting Started tutorial to clarify where and how to add
controller actions, and fix some grammar.

This PR is an improved version of #14828, #14822 and #14815.

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This reverts commit fd6d7835.

We are back on arel master, see b395265f.

This reverts commit 28bd4420.

Reason: Existing text was clearer imo.

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in the "Forms to External Resources" section [skip ci]

Improved version of #14851 after helpful feedback from @robin850 and @matthewd.

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in the Getting Started Guide.

This PR regroups #14817, #14818 and #14819 into one commit.

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We should rely instead on the version supported by Active Record

Closes #14809

The name of the gem is `uglifier` and all other references
use `uglifier`, not `uglify`.

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Extend previous changes, include the default line from the application controller that new rails applications are created with: 
  protect_from_forgery with: :exception

Minor wording changes to align.

I think the changes to the default behaviour mean that rails will throw an exception when an invalid authenticity token is found.  The previous proposed code of calling super then sign_out meant that sign_out was never reached - the exception handler never returned.

I think the best approach now is to catch the exception, although I'm not 100% certain on that.

Currently, the section called "How to store your custom translations"
has several subheadings that make no sense, such as "Translations for
ActiveRecord models." These make more sense under the "Overview of the
I18n API Features" section. I moved the "How to store..." section down
to the more appropriate sub-headings "Using Different Backends" and
"Using Different Exception Handlers" and removed the "Customize your
i18n setup" header.

Calling `to_sym` on user input opens apps up to Denial of Service attacks, via the symbol table being expanded to consume vast swathes of memory.

It is a fairly common configuration to have DNS configured such that all subdomains route to your Rails app, in which case an attacker visits `www1.foo.com`, `www2.foo.com`, and so on until something gives.

It is far less likely to have this problem with TLDs, so that change was only for consistency.

Per discussion at https://github.com/rails/rails/issues/14645#issuecomment-40499409

This was changed in https://github.com/rails/rails/pull/13415/files