Unable to control memory utilization on server increasing with ruby process

I have a Rails 3.2 application running on production server. The server has 8 GB of RAM and every other process works fine. But, there is a ruby process which keeps the memory utilization on the higher side. I have to manually login to the server console and type the TOP command and kill the process using the PID.

But, I am unable to figure out how to check which ruby process is taking so much of memory and also how to control it permanently.

Please suggest me a solution.

Thanks.