Update and fix test kitchet to be conformant with poltergeist

spec/support/kneet_connections.rb

@@ -0,0 +1,10 @@
+class ActiveRecord::Base
+  mattr_accessor :shared_connection
+  @@shared_connection = nil
+
+  def self.connection
+    @@shared_connection || retrieve_connection
+  end
+end
+
+ActiveRecord::Base.shared_connection = ActiveRecord::Base.connection