TJ's India Relish



Can you say YUM?

I'd like to reproduce this excellent chutney-like "India Relish" condiment I
got from TJ's. Here are the ingredients:

Diced tomatoes, onions, canola oil, water, white vinegar, brown sugar,
tamarind, garlic, grated ginger, curry powder, salt, onion seeds, mustard
seeds, cayenne pepper, turmeric.

I don't know where to begin in trying to reproduce this for my personal
pleasure. It could just be more worth the time and energy to buy it
there.... any suggestions otherwise?