Use Travis to build docker images

While our application to Docker Open Source is under review, builds
on DockerHub are not available. Instead, set up travis to build
our docker images.

The full build is done with "docker buildx", which in theory lets
us build images for other architectures. In practice, the normal
build (changing the base image to an arch specific image) works
for ARM but fails in "docker buildx", and I'm not sure exactly why.

.travis.yml

@@ -2,20 +2,49 @@ branches:
   except:
   - "/^wip/"
 language: node_js
-dist: bionic
+dist: focal
 addons:
   firefox: latest-esr
-node_js:
-- '12'
-before_install:
-- mkdir geckodriver/
-- wget https://github.com/mozilla/geckodriver/releases/download/v0.22.0/geckodriver-v0.22.0-linux64.tar.gz
-- tar xvf geckodriver-v0.22.0-linux64.tar.gz -C geckodriver/
-- export PATH="`pwd`/cvc4:`pwd`/geckodriver:$PATH"
-- sudo apt-get update -q -y
-- sudo apt-get install -y pulseaudio graphicsmagick libpulse-dev libcanberra-dev libatlas-base-dev unzip
-- pulseaudio --start
-script:
-- npm run lint
-- LOCALE="en-US" TZ="America/Los_Angeles" npm test
-after_success: npm run coverage
+node_js: '12'
+services:
+- docker
+
+stages:
+  - test
+  - name: docker
+    #if: type = push AND branch = master AND repo = stanford-oval/almond-server
+jobs:
+  include:
+    - name: Test
+      stage: test
+      before_install:
+      - mkdir geckodriver/
+      - wget https://github.com/mozilla/geckodriver/releases/download/v0.22.0/geckodriver-v0.22.0-linux64.tar.gz
+      - tar xvf geckodriver-v0.22.0-linux64.tar.gz -C geckodriver/
+      - export PATH="`pwd`/cvc4:`pwd`/geckodriver:$PATH"
+      - sudo apt-get update -q -y
+      - sudo apt-get install -y pulseaudio graphicsmagick libpulse-dev libcanberra-dev libatlas-base-dev unzip
+      - pulseaudio --start
+      script:
+      - npm run lint
+      - LOCALE="en-US" TZ="America/Los_Angeles" npm test
+      after_success: npm run coverage
+    - name: Docker (portable)
+      stage: docker
+      install:
+      - docker login -u $DOCKER_USERNAME -p $DOCKER_PASSWORD
+      script:
+      - docker build -f Dockerfile.portable -t stanfordoval/almond-server:latest-portable .
+      #after_success:
+      #- docker push stanfordoval/almond-server:latest-portable
+    - name: Docker
+      stage: docker
+      install:
+      - mkdir -vp ~/.docker/cli-plugins/
+      - curl --silent -L "https://github.com/docker/buildx/releases/download/v0.3.0/buildx-v0.3.0.linux-amd64" > ~/.docker/cli-plugins/docker-buildx
+      - chmod a+x ~/.docker/cli-plugins/docker-buildx
+      - docker login -u $DOCKER_USERNAME -p $DOCKER_PASSWORD
+      - docker buildx create --use
+      script:
+      #- docker buildx build --platform linux/amd64,linux/arm64,linux/arm/v7 -t stanfordoval/almond-server:latest --push .
+      - docker buildx build --platform linux/amd64 -t stanfordoval/almond-server:latest .