avoided to call `Marshal.dump` twice

This commit also implements a faster version of #demodulize I was unable
to isolate with git add --patch.

Not a big fan of the name #deconstantize. It complements #demodulize
getting rid of the rightmost constant, hence the name, but it is
unrelated to the well-known #constantize. So unsure. Could not come
with anything better, please feel free to rename.

fix a document for race_condition_ttl. ActiveSupport::Cache::MemoryCache isn't exist.

removed a reference to SynchronizedMemoryStore and CompressedMemCacheStore 

removed reference to SynchronizedMemoryStore and CompressedMemCacheStore (the remaining code from 9cafc288)

Remove trailing "#" on rake routes for controller only routes

method redefined warning removed!

ActiveRecord is no more in controller directory.

This is also faster on 1.9.

Add missing type to number_field_tag documentation

More checks for instance writers.

Test fix Allow instances to disable record_timestamps

Removed here 0d0176c4

Fix railtie configuration test calling PostsController#create which didn'

ActiveModel::Validator only takes one parameter, documentation had two params listed.

Fix deprecation warnings in action pack render tests

Responders now return 204 No Content for API requests without a response body (as in the new scaffold)

Scaffold returns 204 No Content for API requests without content. This makes scaffold work with jQuery out of the box.

Added test case for postgresql database

This should go in your ~/.gitignore.

This reverts commit e75c18bf.