Try to automate Docker builds.

.dockerignore

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+.github
+.vscode
+dist
+dist_injected
+node_modules
+.env
+.env.local

.env.build

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+API_SERVER=__API_URL__
+THEMES_URL=https://static.revolt.chat/themes

.github/workflows/docker.yml

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+name: Docker
+
+on:
+    push:
+        branches:
+            - "master"
+        tags:
+            - "v*"
+    pull_request:
+        branches:
+            - "master"
+
+jobs:
+    docker:
+        runs-on: ubuntu-latest
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v2
+            - name: Docker meta
+              id: meta
+              uses: docker/metadata-action@v3
+              with:
+                  images: name/app
+            - name: Login to DockerHub
+              if: github.event_name != 'pull_request'
+              uses: docker/login-action@v1
+              with:
+                  username: ${{ secrets.DOCKERHUB_USERNAME }}
+                  password: ${{ secrets.DOCKERHUB_TOKEN }}
+            - name: Build and push
+              uses: docker/build-push-action@v2
+              with:
+                  context: .
+                  push: ${{ github.event_name != 'pull_request' }}
+                  tags: ${{ steps.meta.outputs.tags }}
+                  labels: ${{ steps.meta.outputs.labels }}