SSH permissions 0644 for '/home/username/.ssh/id_rsa' are too open.

ssh permissions 0644 for are too open.md

some problem if you have new system, try to deploy on github with old ssh, when you add ssh on terminal (command line) Ubuntu.
wicky@code: eval $(ssh-agent)
Agent pid 7xxx
wicky@code: ssh-add ~/.ssh/id_rsa  #note id_rsa only name not name.pub but only name
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Permissions 0644 for '/home/wicky/.ssh/id_rsa' are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.

you get error like "Permissions 0644 for '/home/username/.ssh/id_rsa' are too open."
its because from old system change with
$ cd  ~/.ssh/ chmod 600 id_rsa 

and try again to add ssh again