Build based on symbolic suite name

This allows for tagging on that as well.  The alias is gotten from the
/etc/devuan_version file.  Only stable is tagged as "latest" so people
get something that ought to work by default.

.gitlab-ci.yml

@@ -5,7 +5,6 @@
 
 variables:
   DEBIAN_VERSION: jessie-20170723
-  DEVUAN_SUITE: jessie
   TZ: UTC
   LC_ALL: C
 
@@ -29,9 +28,9 @@ migrate:
 build:
   stage: build
   script:
-    - ./build.sh "$DEVUAN_SUITE"
+    - ./build.sh stable
 
 derive:
   stage: derive
   script:
-    - ./derive.sh "$DEVUAN_SUITE"
+    - ./derive.sh stable

build.sh

@@ -28,8 +28,14 @@ EOF
 
 docker build -t $IMAGE:$STAMP .
 
+ALIAS=$(docker run --rm $IMAGE:$STAMP cat /etc/devuan_version)
+
 docker push $IMAGE:$STAMP
-docker tag  $IMAGE:$STAMP $IMAGE:$SUITE
+docker tag  $IMAGE:$STAMP $IMAGE:$ALIAS
+docker push $IMAGE:$ALIAS
+docker tag  $IMAGE:$ALIAS $IMAGE:$SUITE
 docker push $IMAGE:$SUITE
-docker tag  $IMAGE:$SUITE $IMAGE
-docker push $IMAGE
+if $SUITE = stable; then
+    docker tag  $IMAGE:$SUITE $IMAGE
+    docker push $IMAGE
+fi

derive.sh

@@ -15,8 +15,14 @@ docker build \
        --tag $IMAGE:$STAMP \
        --file $(basename $IMAGE).df .
 
+ALIAS=$(docker run --rm $IMAGE:$STAMP cat /etc/devuan_version)
+
 docker push $IMAGE:$STAMP
-docker tag  $IMAGE:$STAMP $IMAGE:$SUITE
+docker tag  $IMAGE:$STAMP $IMAGE:$ALIAS
+docker push $IMAGE:$ALIAS
+docker tag  $IMAGE:$ALIAS $IMAGE:$SUITE
 docker push $IMAGE:$SUITE
-docker tag  $IMAGE:$SUITE $IMAGE
-docker push $IMAGE
+if $SUITE = stable; then
+    docker tag  $IMAGE:$SUITE $IMAGE
+    docker push $IMAGE
+fi