update readme with open source install instructions
update readme with open source install instructions

harisgodil-MM/grim,MediaMath/grim,MediaMath/grim,varun06/grim,logie17/grim,harisgodil-MM/grim,bluebytes60/grim,logie17/grim,varun06/grim,bhand-mm/grim,bhand-mm/grim,bluebytes60/grim