How can I run a bash script at the end of startup (ubuntu server 16.04)

Question

My Script

#!/bin/bash
export DISPLAY=:0
my-application start &
chvt 7

• I've tried sticking it in my /etc/init.d directory. (without success)
• Also tried to put it in my rc.local file. (that also didnt work)
• The script itself does run if I run it myself after startup.
• Im also open to figuring out a new way to run my application at startup