Update Dockerfile

Dockerfile

@@ -6,6 +6,8 @@ ENV BRANCH=sta
 #RUN sed -E -i 's#http://[^\s]*archive\.ubuntu\.com/ubuntu#http://ftp.fau.de/ubuntu#g' /etc/apt/sources.list
 #RUN sed -E -i 's#http://[^\s]*ports\.ubuntu\.com/ubuntu-ports#http://ftp.fau.de/ubuntu-ports#g' /etc/apt/sources.list
 
+RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
+
 RUN apt update && apt upgrade -yy && apt install -yy \
   git \
   php php-curl php-xml php-zip p7zip-full && \