fix dockerfile for npm

Dockerfile

@@ -10,7 +10,10 @@ RUN mkdir -p $COMPOSER_HOME && chmod -R 777 $COMPOSER_HOME && curl -sS https://g
   && chmod +x composer.phar && mv composer.phar /usr/local/bin/composer
 
 # Install NPM
-RUN apt-get -yq install nodejs
+RUN curl -sL https://deb.nodesource.com/setup_10.x | bash
+
+# Install NPM
+RUN apt-get -yq install nodejs npm
 
 # Install Sass
 RUN npm install -g sass