Addition of GitHub Actions workflow (#191)

* changed the name of discord token env variable to be consistent with readme.md

* added github actions workflow for building and pushing docker image to dockerhub on release

* changed workflow to actually build and push to dockerhub

* changed workflow to not use variable

* changed workflow to not use a secret for the dockerhub username

.github/workflows/push-docker-image.yml

@@ -6,8 +6,6 @@ on:
 
 jobs:
   push-docker-image:
-    env:
-      docker_repo: simploka/neue
     runs-on: ubuntu-latest
     steps:
       - name: check repository
@@ -16,13 +14,13 @@ jobs:
       - name: login to docker registry
         uses: docker/login-action@v3
         with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          username: simploka
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
       - name: build and push docker image to registry
         uses: docker/build-push-action@v5
         with:
           push: true
           tags: |
-            ${{ docker_repo }}:${{ github.event.release.tag_name }}
-            ${{ docker_repo }}:latest
+            simploka/neue:${{ github.event.release.tag_name }}
+            simploka/neue:latest