Merge pull request #16363 from arthurnn/null_transaction

Null transaction
use `get` instead of accessing the named routes internals
Rename method for clarity

Ruby generally does not use the is_* prefix on predicate methods.
Use available method rather than macro name checking
Fixes small error in ActiveRecord::Reflection docs

[ci skip]
Update README.md
Added Object#self which returns the object itself
Rename Object#self to Object#itself to have parity with matz sanctioned method name for Ruby 2.2
Rename tests too
always return a string from find_script_name

this allows us to avoid nil checks on the return value
just set the host, no need for another hash allocation / merge!
Improve the error message when resque-scheduler is not available
Fix the test requirement of resque_scheduler
copy edits[ci skip]
Merge branch 'master' of github.com:rails/docrails

Conflicts:
	guides/source/testing.md
Deprecate source_macro

`source_macro` is no longer used in any ActiveRecord code. I've
chosen to deprecate it because it was not marked as nodoc and may
be in use outside of rails source.
rename MiniTest to Minitest
Merge pull request #16373 from eileencodes/deprecate-reflection-source_macro

Deprecate source_macro
Merge pull request #16374 from rajcybage/consistency_minitest

rename MiniTest to Minitest
[ci skip] fix markdown