chore: Add CI pipeline (decentraland#370)

* Add CI pipeline

* Only run on push

* Add coveralls

.github/workflows/node.yml

@@ -0,0 +1,50 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  Build-and-test-webapp:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ./webapp
+    steps:
+      - uses: actions/checkout@master
+      - name: Use Node.js 14.x
+        uses: actions/setup-node@v1
+        with:
+          node-version: 14.x
+      - name: Install
+        run: npm ci
+      - name: Build
+        run: npm run build
+      - name: Test
+        run: npm test -- --coverage
+        if: ${{ always() }}
+    finish:
+      needs: test
+      runs-on: ubuntu-latest
+      steps:
+        - name: Coveralls Finished
+          uses: coverallsapp/github-action@master
+          with:
+            github-token: ${{ secrets.github_token }}
+            parallel-finished: true
+  Build-and-test-indexer:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ./indexer
+    steps:
+      - uses: actions/checkout@master
+      - name: Use Node.js 14.x
+        uses: actions/setup-node@v1
+        with:
+          node-version: 14.x
+      - name: Install
+        run: npm ci
+      - name: Build
+        run: |
+          npm run build-data -- --network mainnet
+          npm run codegen
+          npm run build