Getting Started Guide: update RubyGems Guides link [ci skip]
Merge pull request #12335 from francisgo/patch-1

Getting Started Guide: update RubyGems Guides link [ci skip]
Merge pull request #11423 from kennyj/remove_quoted_locking_column

Remove unused quoted_locking_column method.
ActiveRecord::ConnectionAdapters::Column.string_to_time method respects string with timezone. Closes #12278.