build: add missing atlantis user in Debian image

It appears that when #3001 combined the Dockerfiles, the bit that adds
the `atlantis` user was not added to the Debian build stage

Also correct some trailing spaces and missing EOL in
`docker-compose.yml`

Dockerfile

@@ -191,6 +191,13 @@ COPY --from=deps /usr/bin/git-lfs /usr/bin/git-lfs
 # copy docker entrypoint
 COPY docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
 
+# Add atlantis user to Debian as well
+RUN useradd --create-home --user-group --shell /bin/bash atlantis && \
+    adduser atlantis root && \
+    chown atlantis:root /home/atlantis/ && \
+    chmod g=u /home/atlantis/ && \
+    chmod g=u /etc/passwd
+
 # Install packages needed for running Atlantis.
 # We place this last as it will bust less docker layer caches when packages update
 # hadolint ignore explanation

docker-compose.yml

@@ -20,7 +20,7 @@ services:
         ports:
         - '6379:6379'
         command: redis-server --save 20 1 --loglevel warning --requirepass test123
-        volumes: 
+        volumes:
         - redis:/data
     atlantis:
         depends_on:
@@ -39,4 +39,4 @@ services:
 
 volumes:
     redis:
-        driver: local
+        driver: local