Problem
You are working with a git repository but after first cloning the project to your localhost and trying to push changes afterwards, github is asking for you username and password.
Solution
Edit your git configuration and make sure that it uses the git protocol instead of https, so in your ~/project/.git/config file
replace:
remote.origin.url=https://github.com/project_name/repository_name.git
with:
remote.origin.url=git@github.com:project_name/repository_name.git