Merge pull request #23442 from prathamesh-sonpatki/improve-pg-version-old-error-message

Improve pg version old error message and mention this change in release notes.

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -215,7 +215,7 @@ def initialize(connection, logger, connection_parameters, config)
                                         self.class.type_cast_config_to_integer(config.fetch(:statement_limit) { 1000 })
 
         if postgresql_version < 90100
-          raise "Your version of PostgreSQL (#{postgresql_version}) is too old, please upgrade!"
+          raise "Your version of PostgreSQL (#{postgresql_version}) is too old. Active Record supports PostgreSQL >= 9.1."
         end
 
         add_pg_decoders

guides/source/5_0_release_notes.md

@@ -381,6 +381,9 @@ Please refer to the [Changelog][active-record] for detailed changes.
 *   Removed support for the `protected_attributes` gem.
     ([commit](https://github.com/rails/rails/commit/f4fbc0301021f13ae05c8e941c8efc4ae351fdf9))
 
+*   Removed support for PostgreSQL versions below 9.1.
+    ([Pull Request](https://github.com/rails/rails/pull/23434))
+
 ### Deprecations
 
 *   Deprecated passing a class as a value in a query. Users should pass strings