DEV: update Rails to version 6.0.1

This version of Rails eliminates a monkey patch that is no longer needed!

Additionally it preps us for Ruby 2.7 support.

lib/freedom_patches/rails6.rb

@@ -1,57 +0,0 @@
-# frozen_string_literal: true
-
-# see: https://github.com/rails/rails/pull/36949#issuecomment-530698779
-#
-# Without this patch each time we close a DB connection we spin a thread
-
-module ::ActiveRecord
-  module ConnectionAdapters
-    class AbstractAdapter
-      class StaticThreadLocalVar
-        attr_reader :value
-
-        def initialize(value)
-          @value = value
-        end
-
-        def bind(value)
-          raise "attempting to change immutable local var" if value != @value
-          if block_given?
-            yield
-          end
-        end
-      end
-
-      # we have no choice but to perform an aggressive patch here
-      # if we simply hook the method we will still call a finalizer
-      # on Concurrent::ThreadLocalVar
-
-      def initialize(connection, logger = nil, config = {}) # :nodoc:
-        super()
-
-        @connection          = connection
-        @owner               = nil
-        @instrumenter        = ActiveSupport::Notifications.instrumenter
-        @logger              = logger
-        @config              = config
-        @pool                = ActiveRecord::ConnectionAdapters::NullPool.new
-        @idle_since          = Concurrent.monotonic_time
-        @visitor = arel_visitor
-        @statements = build_statement_pool
-        @lock = ActiveSupport::Concurrency::LoadInterlockAwareMonitor.new
-
-        if self.class.type_cast_config_to_boolean(config.fetch(:prepared_statements) { true })
-          @prepared_statement_status = Concurrent::ThreadLocalVar.new(true)
-          @visitor.extend(DetermineIfPreparableVisitor)
-        else
-          #@prepared_statement_status = Concurrent::ThreadLocalVar.new(false)
-          @prepared_statement_status = StaticThreadLocalVar.new(false)
-        end
-
-        @advisory_locks_enabled = self.class.type_cast_config_to_boolean(
-          config.fetch(:advisory_locks, true)
-        )
-      end
-    end
-  end
-end