Enable HTTP requests

Dockerfile

@@ -44,7 +44,7 @@ RUN { \
     } > /usr/local/etc/php/conf.d/php-recommended.ini
 
 RUN pecl install apcu \
-    && pecl install yaml-2.0.4 \
+    && pecl install yaml-2.1.0 \
     && docker-php-ext-enable apcu yaml
 
 # Set user to www-data
@@ -64,6 +64,9 @@ RUN curl -o grav-admin.zip -SL https://getgrav.org/download/core/grav-admin/${GR
 # Create cron job for Grav maintenance scripts
 RUN (crontab -l; echo "* * * * * cd /var/www/html;/usr/local/bin/php bin/grav scheduler 1>> /dev/null 2>&1") | crontab -
 
+# Accept incoming HTTP requests
+EXPOSE 80/tcp
+
 # Return to root user
 USER root