Revert "replace docker-entrypoint with latest (#69)"

[JalexChen]

This reverts commit 85c937f.

Reverting commit due to:

1. Dockerfile builds image successfully, however, the test cannot accept connections, despite the db instance saying it can
2. using docker-entrypoint.sh pulled from source makes the build not deterministic
3. Opens Update Docker Entrypoint #61 back up