Update Dockerfile

Dockerfile

@@ -5,6 +5,7 @@ WORKDIR /var/www/peertube
 RUN useradd -m -d /var/www/peertube -s /bin/bash -p peertube peertube && echo "peertube:peertube" | chpasswd
 #&& chown peertube:peertube /var/www/peertube
 
+RUN apt-get install curl
 RUN $ VERSION=$(curl -s https://api.github.com/repos/chocobozzz/peertube/releases/latest | grep tag_name | cut -d '"' -f 4) && echo "Latest Peertube version is $VERSION, current version is $PEERTUBE_VER"
 RUN cd /var/www/peertube && -u peertube mkdir config storage versions
 RUN cd versions && -u peertube wget -q "https://github.com/Chocobozzz/PeerTube/releases/download/${VERSION}/peertube-${VERSION}.zip"