Feature/improve dockerhub deployment (#98)

* Add docker deployment for Github actions

* Add docker specs for the release of tagged and latest versions, also add specs for nightly builds

Co-authored-by: Denis Granha <denis@gnosis.pm>

.github/workflows/deploy-docker-nightly.yml

@@ -0,0 +1,29 @@
+name:                           Docker Image Nightly Release
+
+# Run "nightly" build on each commit to "dev" branch.
+on:
+  push:
+    branches:
+      - dev
+
+jobs:
+  deploy-docker:
+    name:                       Build Release
+    runs-on:                    ubuntu-latest
+    steps:
+      - name:                   Checkout sources
+        uses:                   actions/checkout@master
+      - name:                   Install toolchain
+        uses:                   actions-rs/toolchain@v1
+        with:
+          toolchain:            stable
+          profile:              minimal
+          override:             true
+      - name:                   Deploy to docker hub
+        uses: elgohr/Publish-Docker-Github-Action@master
+        with:
+          name: openethereum/openethereum
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+          dockerfile: scripts/docker/alpine/Dockerfile
+          tags: "nightly"