vagrant@homestead:/usr/share/nginx/html/laravel-blog$ sudo composer install
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Installation request for doctrine/instantiator 1.0.3 -> satisfiable by doctrine/instantiator[1.0.3].
- doctrine/instantiator 1.0.3 requires php ~5.3 -> your PHP version (7.0.3) does not satisfy that requirement.
Problem 2
- doctrine/instantiator 1.0.3 requires php ~5.3 -> your PHP version (7.0.3) does not satisfy that requirement.
- phpunit/phpunit-mock-objects 2.3.0 requires doctrine/instantiator ~1.0,>=1.0.1 -> satisfiable by doctrine/instantiator[1.0.3].
- Installation request for phpunit/phpunit-mock-objects 2.3.0 -> satisfiable by phpunit/phpunit-mock-objects[2.3.0].

composer install --ignore-platform-reqs

composer update --ignore-platform-reqs

Cannot create cache directory /home/vagrant/.composer/cache/repo/https---packagist.org/, or directory is not writable. Proceeding without cache
Cannot create cache directory /home/vagrant/.composer/cache/files/, or directory is not writable. Proceeding without cache

sudo chmod -R 777 /home/vagrant/.composer/cache/files/

composer config -g repo.packagist composer https://packagist.phpcomposer.com