Add CircleCI config.

Signed-off-by: Yahor Berdnikau <egorr.berd@gmail.com>

.circleci/config.yml

@@ -0,0 +1,25 @@
+version: 2
+jobs:
+  build:
+    docker:
+      - image: circleci/android:api-26-alpha
+    working_directory: ~/ultrasonic
+    envoronment:
+      JVM_OPTS: -Xmx3200m
+    steps:
+      - checkout
+      - restore_cache:
+          key: gradle-cache-{{ checksum "dependencies.gradle" }}
+      - run:
+          name: checkstyle
+          command: ./gradlew -Pqc ktlintCheck
+      - run:
+          name: build
+          command: ./gradlew assembleDebug
+      - run:
+          name: unit-tests
+          command: ./gradlew test
+      - save_cache:
+          paths:
+            - ~/.gradle
+          key: gradle-cache-{{ checksum "dependencies.gradle" }}