Fixed error with memcached when running php-worker

php-worker/Dockerfile

@@ -37,7 +37,11 @@ RUN apk --update add wget \
   supervisor
 
 RUN docker-php-ext-install mysqli mbstring pdo pdo_mysql tokenizer xml pcntl
-RUN pecl channel-update pecl.php.net && pecl install memcached mcrypt-1.0.1 mongodb && docker-php-ext-enable memcached mongodb
+RUN if [ $(php -r "echo PHP_MAJOR_VERSION;") = "5" ]; then \
+  pecl channel-update pecl.php.net && pecl install memcached-2.2.0 mcrypt-1.0.1 mongodb && docker-php-ext-enable memcached mongodb \
+;else \
+  pecl channel-update pecl.php.net && pecl install memcached mcrypt-1.0.1 mongodb && docker-php-ext-enable memcached mongodb \
+;fi
 
 # Add a non-root user:
 ARG PUID=1000