Add install-composer.sh script.

scripts/install-composer.sh

@@ -0,0 +1,36 @@
+#!/bin/sh
+
+set -e
+
+VERSION="$1"
+
+# NOTE: we should have better protections here
+php -r "copy('https://getcomposer.org/installer', '/tmp/composer-setup.php');"
+
+# Allow for a few convenience install methods
+if [ "$VERSION" = '1-latest' ]; then
+  php /tmp/composer-setup.php --install-dir=/usr/local/bin --filename=composer --1
+elif [ "$VERSION" = '1' ]; then
+  php /tmp/composer-setup.php --install-dir=/usr/local/bin --filename=composer --1
+elif [ "$VERSION" = '2-latest' ]; then
+  php /tmp/composer-setup.php --install-dir=/usr/local/bin --filename=composer --2
+elif [ "$VERSION" = '2' ]; then
+  php /tmp/composer-setup.php --install-dir=/usr/local/bin --filename=composer --2
+elif [ "$VERSION" = 'preview' ]; then
+  php /tmp/composer-setup.php --install-dir=/usr/local/bin --filename=composer --preview
+elif [ "$VERSION" = 'snapshot' ]; then
+  php /tmp/composer-setup.php --install-dir=/usr/local/bin --filename=composer --snapshot
+else
+  php /tmp/composer-setup.php --install-dir=/usr/local/bin --filename=composer --version="$VERSION"
+fi
+
+# Remove the setup script
+php -r "unlink('/tmp/composer-setup.php');"
+
+# Check if anything is installed globally
+if [ -f /var/www/.composer/composer.json ]; then
+  # If this is version 2 then let's make sure hirak/prestissimo is removed
+  if composer --version 2>/dev/null | grep -E "Composer (version )?2." > /dev/null; then
+    composer global remove hirak/prestissimo
+  fi
+fi