Add CircleCI configuration

build.gradle

@@ -32,3 +32,15 @@ ext {
 task clean(type: Delete) {
     delete rootProject.buildDir
 }
+
+project.ext.preDexLibs = !project.hasProperty('disablePreDex')
+
+subprojects {
+    project.plugins.whenPluginAdded { plugin ->
+        if ("com.android.build.gradle.AppPlugin" == plugin.class.name) {
+            project.android.dexOptions.preDexLibraries = rootProject.ext.preDexLibs
+        } else if ("com.android.build.gradle.LibraryPlugin" == plugin.class.name) {
+            project.android.dexOptions.preDexLibraries = rootProject.ext.preDexLibs
+        }
+    }
+}

circle.yml

@@ -0,0 +1,23 @@
+machine:
+  java:
+    version: openjdk8
+
+dependencies:
+  pre:
+    - echo y | android -s update sdk -u -a -t "tools"
+    - mkdir -p $ANDROID_HOME/licenses
+    - echo -e "8933bad161af4178b1185d1a37fbf41ea5269c55" > $ANDROID_HOME/licenses/android-sdk-license
+    - echo -e "84831b9409646a918e30573bab4c9c91346d8abd" > $ANDROID_HOME/licenses/android-sdk-preview-license
+    - $ANDROID_HOME/tools/bin/sdkmanager "platform-tools"
+    - $ANDROID_HOME/tools/bin/sdkmanager "extras;m2repository;com;android;support;constraint;constraint-layout;1.0.2"
+    - $ANDROID_HOME/tools/bin/sdkmanager "extras;m2repository;com;android;support;constraint;constraint-layout-solver;1.0.2"
+  override:
+    - ./gradlew app:dependencies
+
+compile:
+  override:
+    - ./gradlew clean assembleRelease -PdisablePreDex
+
+test:
+  override:
+    - ./gradlew testRelease -PdisablePreDex