In a 4-ounce canning jar, mix together the vinegar, water, yellow mustard seeds, brown mustard seeds, curry powder, turmeric, crushed chilies, grated ginger, cardamom, and cumin. Cover and allow to sit in the refrigerator for 2 days. Pour the mixture into a blender or food processor with the sugar and salt and blend until it turns into a coarse paste. Keep refrigerated, use within 2 months.