Model's datetime field is stored differently on heroku from localhost - ruby-on-rails

Question

Steps:
On my localhost server I select the time Jan 18, 2013 10 am - 11 am in my browser located in the Pacific time zone. I then select the exact same time on my production server on heroku.
As you can see the outputs of what is saved to the database are different. I want production to behave as localhost and take into account the timezone when storing the time as UTC. What is causing this? The heroku server is in EST, but that does not account for this behavior.
Controller:
def create
puts params[:event][:starts_at]
#event = Event.create!(params[:event])
puts #event.starts_at
end
Output Localhost:
Fri Jan 18 2013 10:00:00 GMT-0800 (PST)
2013-01-18 18:00:00 UTC
Output Heroku (production):
Fri Jan 18 2013 10:00:00 GMT-0800 (PST)
2013-01-18 10:00:00 UTC
Schema:
t.datetime "starts_at"
Env:
Ruby on Rails 3.2.11
Ruby 1.9.3
Postgres

Answer 1

Background on how PostgreSQL deals with date/time
I think your issue is covered in this answer from another SO question:
Ignoring timezones altogether in Rails and PostgreSQL
Specifically this answer:
https://stackoverflow.com/a/9576170/33204
Use this query for time in UTC format:
SELECT * FROM tbl WHERE time_col > (now() AT TIME ZONE 'UTC')::time
Use this query for time in local timezone:
SELECT * FROM tbl WHERE time_col > now()::time
Rails & ActiveRecords & date/time
This rails/rails github issue also discusses it:
ActiveRecord converts time to default zone on write; assumes UTC on read
There is a comment by pixeltrix which says the following:
#deathbob sorry for the late reply - the accepted values for
config.active_record.default_timezone are either :utc or :local. If
you set it to something other than :utc it will assume :local so what
you're seeing is the expected behavior.
To fix the time in ActiveRecords so that it is always dealt with as UTC you can set the following variable:
config.active_record.default_timezone = :utc

Answer 2

The solution by #slm of config.active_record.default_timezone = :utc did not work for me. Rails was still writing with local and reading with UTC on Heroku.
So I then tried:
config.time_zone = 'Sydney'
config.active_record.default_timezone = :local
Which was still working fine in development but caused the datetime values to now be read in a UTC format from postgres on Heroku.
My temporary workaround solution was to set the default timezone on Heroku with:
heroku config:add TZ="Australia/Sydney"
This is only a temporary solution as I would like my app to use UTC. I have posted to the rails/github issue mentioned by #slm for clarification. I will update my answer when I find a more concrete solution.