Change trigger to push events and add image test

.github/workflows/docker.yml

@@ -1,19 +1,10 @@
 name: build catadog
 
 on:
-  # for testing
-  pull_request:
+  # trigger catadog every time a push occurs on any branch
+  push: 
     branches:
       - "**"
-  # trigger catadog every time a push occurs on any branch
-  # push: 
-  #   branches:
-  #     - "**"
-
-# map of variables that are available to all jobs in the workflow
-# env:
-#   REGISTRY: ghcr.io
-#   REPO: datadog/catadog
 
 jobs:
   build:
@@ -23,3 +14,7 @@ jobs:
         uses: actions/checkout@v4
       - name: build image
         run: docker buildx build -t catadog .
+      - name: test image by starting up a container
+        run: docker run --rm -it --name catadog catadog
+      - name: kill container
+        run: docker container kill catadog