docker exec -it <container ID> docker-php-ext-install pdo pdo_mysql
FROM php:5.6-apache
RUN docker-php-ext-install pdo pdo_mysql
COPY my-php-files/ /var/www/html/
FROM php:5-fpm-alpine
RUN apk add --no-cache git bash tini memcached php5-pcntl php5-common php5-openssl php5-json php5-phar php5-zlib php5-xml php5-curl php5-dom php5-pdo php5-memcache php5-mysql php5-pdo_mysql
&& docker-php-ext-install pcntl pdo_mysql mysql json
&& docker-php-ext-enable pcntl pdo_mysql mysql json