deps.sh: Add composer and phpstan

Add composer and phpstan for ci
Related to coala#1426

.ci/deps.sh

@@ -171,6 +171,17 @@ if [ ! -e ~/.local/tailor/tailor-latest ]; then
   ln -s ~/.local/tailor/tailor-* ~/.local/tailor/tailor-latest
 fi
 
+# Setting Composer and adding phpstan/phpstan.
+if [ ! -e ~/vendor/bin/phpstan ]; then
+sudo php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
+sudo php -r "if (hash_file('SHA384', 'composer-setup.php') === '55d6ead61b29c7bdee5cccfb50076874187bd9f21f65d8991d46ec5cc90518f447387fb9f76ebae1fbbacf329e583e30') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"
+sudo php composer-setup.php
+sudo php -r "unlink('composer-setup.php');"
+sudo apt-get install php
+composer require phpstan/phpstan
+export PATH="/vendor/bin/:$PATH"
+fi
+
 # making coala cache the dependencies downloaded upon first run
 echo '' > dummy
 coala-ci --bears CheckstyleBear --files dummy --no-config --bear-dirs bears || true