Make Dockerfile work

Dockerfile

@@ -21,6 +21,7 @@ RUN sed -ri -e 's!/var/www/!${APACHE_DOCUMENT_ROOT}!g' /etc/apache2/apache2.conf
 
 # Install and Run composer
 COPY composer.sh /tmp/composer.sh
+RUN chmod u+x /tmp/composer.sh
 RUN /tmp/composer.sh
 RUN php composer.phar install --working-dir /var/www/studip/
 

composer.sh

+#!/bin/sh
+
+EXPECTED_CHECKSUM="$(php -r 'copy("https://composer.github.io/installer.sig", "php://stdout");')"
+php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
+ACTUAL_CHECKSUM="$(php -r "echo hash_file('sha384', 'composer-setup.php');")"
+
+if [ "$EXPECTED_CHECKSUM" != "$ACTUAL_CHECKSUM" ]
+then
+    >&2 echo 'ERROR: Invalid installer checksum'
+    rm composer-setup.php
+    exit 1
+fi
+
+php composer-setup.php --quiet
+RESULT=$?
+rm composer-setup.php
+exit $RESULT
\ No newline at end of file