Rails 6.1 support (#853)

* use ActiveRecord::ConnectionAdapters::SchemaCreation for rails 6.1

* use just **args instead of options, **args in SQLServerRealTransaction

* only use updated initialize arguments in SQLServerRealTransaction for rails 6.1

* fix for type_cast_calculated_value has already been applied to rails 5.2, so we don't need to it anymore

* Remove backward compatible code

Co-authored-by: Wanderson Policarpo <wpolicarpo@gmail.com>

Author: lk0001

lib/active_record/connection_adapters/sqlserver/core_ext/calculations.rb

@@ -31,15 +31,6 @@ def calculate(operation, column_name)
           def build_count_subquery(relation, column_name, distinct)
             super(relation.unscope(:order), column_name, distinct)
           end
-
-          def type_cast_calculated_value(value, type, operation = nil)
-            case operation
-            when "count"   then value.to_i
-            when "sum"     then type.deserialize(value || 0)
-            when "average" then value&.respond_to?(:to_d) ? value.to_d : value
-            else type.deserialize(value)
-            end
-          end
         end
       end
     end

lib/active_record/connection_adapters/sqlserver/schema_creation.rb

@@ -3,7 +3,7 @@
 module ActiveRecord
   module ConnectionAdapters
     module SQLServer
-      class SchemaCreation < AbstractAdapter::SchemaCreation
+      class SchemaCreation < SchemaCreation
         private
 
         def visit_TableDefinition(o)

lib/active_record/connection_adapters/sqlserver/transaction.rb

@@ -31,9 +31,9 @@ def current_isolation_level
     module SQLServerRealTransaction
       attr_reader :starting_isolation_level
 
-      def initialize(connection, options, **args)
+      def initialize(connection, isolation: nil, joinable: true, run_commit_callbacks: false)
         @connection = connection
-        @starting_isolation_level = current_isolation_level if options[:isolation]
+        @starting_isolation_level = current_isolation_level if isolation
         super
       end