add base entrypoint to ec2 image

docker/Dockerfile.ec2.linux.amd64

@@ -25,6 +25,8 @@ ENV PIP_PACKAGES="\
     pycrypto \
 "
 
+COPY ./gce-entrypoint.sh /docker-entrypoint.sh
+
 RUN \
     apk update \
     && apk add --update --no-cache ${PACKAGES} \
@@ -36,3 +38,4 @@ RUN \
     && chmod 700 /root/.ssh
 
 USER root
+ENTRYPOINT ["/docker-entrypoint.sh"]

ec2-entrypoint.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -o pipefail
+set -o errtrace
+set -o nounset
+set -o errexit
+
+if [ "${MOLECULE_CUSTOM_MODULES_REPO}" ]; then
+    mkdir ./library/
+    git clone "$MOLECULE_CUSTOM_MODULES_REPO" ./library/
+fi