Updates reset_counters to allow counter name in params

Add support for counter name to be passed as parameter
on `CounterCache::ClassMethods#reset_counters`. This is
to be consistent with the other methods in the module
that all accept counter name.
fix symbol
Merge pull request #15147 from regonn/fix-symbol

Fix symbol at guides getting_started.md
Fix app generator test hanging.
Merge pull request #15150 from xtian/fix-railties-tests

Fix app generator test hanging.
Add missing tests for column type cast behavior
New applications should be created with json serializer

The fix introduced at 75ba7425f6d235f254c00a45a58f42e88f80301a were
missing this case.

To fix the original issue mentioned at that commit the correct is to
remove update_config_files from the command list since we should not run
both config_files command when creating a new application.

Tests were added to make sure everything is working fine.
Merge pull request #15149 from sgrif/sg-missing-tests

Add missing tests for column type cast behavior
Collected TimeZone's class methods together

Just moved class methods up in file and moved `def self.` methods into `class << self`.
Merge pull request #15152 from printercu/patch-5

Collected TimeZone's class methods together
Document method visibility for designing API docs. [ci skip]

cc https://github.com/rails/rails/issues/14848#issuecomment-41198795
Merge pull request #14428 from jnormore/reset_counters_alias

Updates reset_counters to allow counter name in params
Remove dead test code for unsupported adapters
Merge pull request #15137 from sgrif/sg-remove-dead-code

Remove dead test code for unsupported adapters