Add ZipArchive

Added ZipArchive/ZIP in order to be able to install ICEcoder plugins.

Dockerfile

@@ -2,7 +2,12 @@ FROM php:alpine
 
 LABEL maintainer="Griefed <griefed@griefed.de>"
 
-RUN apk add --no-cache git      && \
+RUN apk update && apk upgrade   && \
+    apk add libzip-dev          && \
+    docker-php-ext-install zip  && \
+    apk add --no-cache git      && \
+    apk add php-zip             && \
+    apk add php7-zip            && \
     mkdir /opt/icecoder         && \
     cd /opt/icecoder            && \
     git clone https://github.com/mattpass/ICEcoder.git ./