add docker build and push to github actions

.github/workflows/gobuild.yml

@@ -3,7 +3,7 @@ on:
   push:
   pull_request:
 jobs:
-  build:
+  validate:
     runs-on: ubuntu-latest
     env:
       GO111MODULE: on
@@ -12,22 +12,44 @@ jobs:
     steps:
     - name: Checkout Terrascan
       uses: actions/checkout@v1
+
     - name: Setup Go
       uses: actions/setup-go@v1
       with:
         go-version: 1.14
+
     - name: Install golint
-      run: |
-        go get -u golang.org/x/lint/golint
+      run: go get -u golang.org/x/lint/golint
+
     - name: Go validations
-      run: |
-        echo Workflow trigger - ${{ github.event_name }}
-        make validate
+      run: make validate
+
     - name: Build Terrascan
-      run: |
-        make build
+      run: make build
+
     - name: Run unit tests
-      run: |
-        make unit-tests
+      run: make unit-tests
+
     - name: Upload coverage to Codecov
       uses: codecov/codecov-action@v1
+
+  # push image to Docker Hub
+  push:
+    # Ensure "validate" job passes before pushing image.
+    needs: validate
+
+    runs-on: ubuntu-latest
+    if: github.event_name == 'push'
+
+    steps:
+    - name: Checkout Terrascan
+      uses: actions/checkout@v1
+
+    - name: Build Terrascan docker image
+      run: make docker-build
+
+    - name: Login to docker hub
+      run: echo "${{ secrets.DOCKER_HUB_TOKEN }}" | docker login -u accurics --password-stdin
+
+    - name: Push Terrascan docker image
+      run: make docker-push