Merge git repo as another branch

I have two local repository on my directory api-php and api-nodejs. I want to have one repo called api with two branch php and nodejs.

$cd api-php
$git remote add nodejs ../api-nodejs
$git remote update
$git checkout -b nodejs
$git rm -f *
$git merge nodejs/master 
$git push -f

By the way, both php and node js implement the same api but the language is totally differnet.
It is best to put both project on separate repository.

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Merge git repo into branch of another repo