drop the flipper_ir_update.py in to the scripts directory in your firmware repo, connect the flipper via usb, and run the following command from the root of the firmware
python ./scripts/flipper_ir_update.py path/to/IRDB/repo/
if there is no repo located, it will clone the IRDB to the directory and transfer the relevent files to the flipper.
if the repo exists it will update it and transfer the relevent files to the flipper.