Cleanup actions and setup docker build cache

.github/workflows/tests.yml

@@ -0,0 +1,40 @@
+name: Tests
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  test-api:
+    name: Test API
+    runs-on: ubuntu-latest
+
+    defaults:
+      run:
+        working-directory: api
+
+    steps:
+      - name: Set up Go 1.x
+        uses: actions/setup-go@v2
+        with:
+          go-version: ^1.13
+        id: go
+
+      - name: Check out code into the Go module directory
+        uses: actions/checkout@v2
+
+      - name: Get dependencies
+        run: |
+          go get -v -t -d ./...
+          if [ -f Gopkg.toml ]; then
+              curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh
+              dep ensure
+          fi
+
+      - name: Build
+        run: go build -v .
+
+      - name: Test
+        run: go test -v ./...