Fixed error with async

lib/blazer/run_statement_job.rb

@@ -8,7 +8,7 @@ module Blazer
     def perform(result, data_source, statement, options)
       begin
         ActiveRecord::Base.connection_pool.with_connection do
-          data_source.connection_model.connection_pool.with_connection do
+          data_source.adapter.connection_model.connection_pool.with_connection do
             result << RunStatement.new.perform(data_source, statement, options)
           end
         end