Move the constantly-changing stuff to *after* the big package install

Move the constantly-changing stuff to after the big package install

Without this, builds take for-fucking-ever.

diff --git a/Dockerfile b/Dockerfile
index 302364d..b297019 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,9 +6,6 @@ RUN useradd mobystash -s /bin/bash -m -U --create-home
 
 COPY Gemfile Gemfile.lock mobystash.gemspec /home/mobystash/
 
-ARG GIT_REVISION=invalid-build
-ENV MOBYSTASH_GIT_REVISION=$GIT_REVISION
-
 RUN DEBIAN_FRONTEND=noninteractive apt-get update \
 	&& DEBIAN_FRONTEND=noninteractive apt-get -y dist-upgrade \
 	&& DEBIAN_FRONTEND=noninteractive apt-get -y install --no-install-recommends \
@@ -27,6 +24,9 @@ RUN DEBIAN_FRONTEND=noninteractive apt-get update \
 	&& ( find /var/tmp -mindepth 1 -maxdepth 1 -delete || true ) \
 	&& ( find /tmp -mindepth 1 -maxdepth 1 -delete || true )
 
+ARG GIT_REVISION=invalid-build
+ENV MOBYSTASH_GIT_REVISION=$GIT_REVISION
+
 COPY lib /home/mobystash/lib
 
 COPY bin/* /usr/local/bin/

GitHub sha: c2a478de