Add a README

And update build.gradle based on what Android Studio 2.1 asked me to do.

Change-Id: I5e27a682d66e91d5423d8eb4788cb42b906d2de4
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..2c2670c
--- /dev/null
+++ b/README.md
@@ -0,0 +1,23 @@
+# TODOs demo: Syncbase and Firebase
+
+This is a TODOs application for Android which uses either Firebase or Syncbase
+as a persistence layer.
+
+## Building & running
+
+- Install [Android Studio](http://developer.android.com/tools/studio/index.html)
+- Open a project rooted in this directory
+
+## Switching between persistence layers
+
+To switch between Firebase and Syncbase use: `Build -> Select Build Variant`
+and choose between the various options (e.g., `firebaseDebug`, `syncbaseDebug` etc.)
+
+### Firebase
+
+The firebase app is at https://vivid-heat-7354.firebaseio.com/.
+Ross Wang and Alex Fandrianto manage the administration of the database.
+
+*WARNING*: There is no authentication required in this demo, and the TODO list
+is global, accessible to all. In a real TODOs app this would not be the case of
+course. In the mean time, don't put anything sensitive there!
diff --git a/build.gradle b/build.gradle
index dd6ee1f..e75adfe 100644
--- a/build.gradle
+++ b/build.gradle
@@ -6,7 +6,7 @@
         maven { url "https://jitpack.io" }
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.0.0'
+        classpath 'com.android.tools.build:gradle:2.1.0'
 
         // Use the Android SDK manager, which will automatically download
         // the required Android SDK.