Submitting two tables/model data with single/two form on one webpage with single submit button?

My issue is simple, lets say I have two models/tables named 'abc' and 'pqr', both has three columns as 'a','b','c' in abc and 'p','q','r' in pqr.

what I want to do is to create a single webpage. On that webpage I want to create a single form which will submit the data for two models/table with single button. May be I will create two form but I want only one submit button. How do solve this issue in ruby on rails.

As in rails we have one model per table.