[CI] Build release apk's (#639)

Add separate workflow for building and siigning APKs

.circleci/config.yml

@@ -3,7 +3,7 @@ machine:
   environment:
     GRADLE_OPTS: '-Dorg.gradle.jvmargs="-Xmx2048m -XX:+HeapDumpOnOutOfMemoryError"'
 jobs:
-  build:
+  test:
     working_directory: ~/code
     docker:
       - image: circleci/android:api-27-alpha
@@ -31,3 +31,31 @@ jobs:
           destination: reports
       - store_test_results:
           path: app/build/test-results
+  build:
+    working_directory: ~/code
+    docker:
+      - image: circleci/android:api-27-alpha
+    environment:
+      JVM_OPTS: -Xmx3200m
+    steps:
+      - checkout
+      - restore_cache:
+          key: jars-{{ checksum "build.gradle" }}-{{ checksum  "app/build.gradle" }}
+      - run:
+          name: Build apk
+          command: |
+            ./gradlew assembleRelease --no-daemon --stacktrace
+            /opt/android/sdk/build-tools/27.0.3/zipalign -v -p 4 app/build/outputs/apk/release/app-release-unsigned.apk app-release-aligned.apk
+            keytool -genkey -v -keystore debug.keystore -alias androiddebugkey -storepass android -keypass android -keyalg RSA -dname "C=US, O=Android, CN=Android Debug"
+            /opt/android/sdk/build-tools/27.0.3/apksigner sign --ks debug.keystore --out app-release.apk --ks-pass pass:android app-release-aligned.apk
+      - store_artifacts:
+          path: app-release.apk
+          destination: app-release.apk
+workflows:
+  version: 2
+  test-and-build:
+    jobs:
+      - test
+      - build:
+          requires:
+            - test