Composer could not find a composer.json

To install composer and add to your global path:

curl -sS https://getcomposer.org/installer | php
mv composer.phar /usr/local/bin/composer

run these in terminal. It does say if you get an error that usr doesn't exist, you do need to manually make it. I know an answer was selected, so this is for anyone who may see this in the future, as i am sometimes, and don't want to be advised to visit yet another site. Its simple just two lines, might have to be in sudo if you have permission error

You are in wrong directory. cd to your project directory then run composer update.