ruby on rails - Timestamp breaks sqlite3 import to postgresql -

I have a rail app that I used to use for DB, but now switch to using PostGrussle I am here.

I have installed PostgreSQL database, and now I am importing sqlite3 db in postgre using Tuck Gem.

The problem is: My SQL is a column of 3dB: The time in which I store the Unix timestamp (integer) Postgres schema says that they are 'timestamp without time zone', and current Prices are rejected. This error is:

  PG :: error: error: column is the type of timestamp without "time" time zone, but the expression type is the integer (Sequel :: DatabaseError) LINE 1:. . "Address_type", "Medicine") Price (2, 2, 0, zero, 1367688600 ...) How can you get around this? Need to change to match the postgres schema in my SQL 3 database? Also, since Only my dev is for DB, so there is no problem to completely drop the DB value and start it again - so if there is an easy way to do it also to appreciate that.   
 
 
 To convert the value back you will need to run it through the query:  
  select time with time zone 'era' + timecode * interval '1 second';   
 If I change my schema in PostgreSQL, these columns are integers, then I will run them through the job which will add a new timestamp column, and the above name is the column name of MacCl's old timestamp). Once you've checked the data, you can skip the old columns and replace the new column with the old name.