Q:

How to insert created_date in PostgreSQL using ruby on rails

I have a table called users in a PostgreSQL database.  It has name, country and created_date columns.  If I insert a new user record with name and country values, created_date got inserted automatically.  When I tried to do the same using Ruby code, created_date field is null.   My definition for create is given below.  How can I insert created_date automatically. 
def create
    @new_user = User.new(params[:user])
    @new_user.save
end

Note: params[:user] contains name and country values

A:

Rails will automatically manage only created_on and created_at columns as you can see from ActiveRecord::Timestamp source.  Difference between _at and _on is that _at contains full datetime, while _on contains only date.  If you use migrations you can create 'created_at' and 'updated_at' with t.timestamps.