Can someone explain this to please and what I can do
to sort out my permissions issue. Its seems to be stopping me from
getting the authenticity of host heroku
I would recommend you to re create a set of keys using
ssh-keygen -t rsa -C '<email>'
for a more secure system. Else changing the permissions to something less open would do.
To change permissions, use
chmod 400 ~/.ssh/id_rsa
Just change the permission of the /.ssh/id_rsa file to 400
#chmod 400 ~/.ssh/id_rsa
This won't make others or from any group members to modify the file.
Simply reset permissions to your key files to defaults
sudo chmod 600 ~/.ssh/id_rsa
sudo chmod 600 ~/.ssh/id_rsa.pub