Add npm

Dockerfile

@@ -17,7 +17,7 @@ RUN apk update && \
     ln -s /lib/libz.so.1 /usr/glibc-compat/lib/ && \
     ln -s /lib/libc.musl-x86_64.so.1 /usr/glibc-compat/lib && \
     \
-    apk add --no-cache bash python nodejs git unzip \
+    apk add --no-cache bash python nodejs npm git unzip \
         php7 php7-phar php7-json php7-dom php7-gd php7-mbstring php7-openssl \
         php7-pdo php7-curl php7-xml php7-zip php7-session php7-ctype \
         php7-tokenizer php7-simplexml php7-xmlwriter && \