Does anyone have any methods of applying a color ramp to a grayscale image? 

I have a NDVI calculated image I am trying to apply color ramp for the decimal based value ranges, but have no idea how to accomplish this.  I was wandering if this was possible via any of the rasterio libraries, and, if so, how would one go about accomplishing this?  I have other band based calculations I'd like to attempt, but until I can figure out how to apply the color ramps, I am at a stand still.

Thanks,