on second thought, use mirror:// urls

Dockerfile

@@ -8,6 +8,17 @@ ARG STEEMD_REV=master
 ARG SECP256K1_REPO=https://github.com/bitcoin/secp256k1
 ARG SECP256K1_REV=master
 
+ARG UBUNTU_MIRROR=mirror://mirrors.ubuntu.com/mirrors.txt
+
+RUN sed -i \
+    -e s#http://archive.ubuntu.com/ubuntu/#${UBUNTU_MIRROR}#g \
+    -e s#http://security.ubuntu.com/ubuntu/#${UBUNTU_MIRROR}#g \
+        /etc/apt/sources.list ; \
+        grep -v deb-src /etc/apt/sources.list > \
+            /etc/apt/sources.list.new && \
+        mv /etc/apt/sources.list.new /etc/apt/sources.list && \
+        cat /etc/apt/sources.list
+
 RUN \
     apt-get update && \
     apt-get install -y \