cmsdk: Update README

Change-Id: Iebc423e92b5357947406bd3b4cc7322bc9a10490

README.md

@@ -1,3 +1,37 @@
-## WIKI
+# CyanogenMod Platform SDK
 
-For any inquiries regarding this project, please reference the [wiki](https://github.com/CyanogenMod/cm_platform_sdk/wiki)
+The Platform SDK provides a set of APIs that give you easy access to a variety of different features within CyanogenMod. The SDK exposes APIs and system level framework access in the Android framework that aren't available in any other distribution.
+
+## Setup
+
+You can either [download](https://github.com/CyanogenMod/android_prebuilts_cmsdk/tree/master/current) from prebuilts hosted on github or pull directly via Gradle.
+
+Within `build.gradle` make sure your `repositories` list sonatype OSS repos
+
+```
+repositories {
+    maven {
+        url "https://oss.sonatype.org/content/repositories/snapshots/"
+    }
+}
+```
+
+To target the current release (for retail devices), set your `dependency` for `1.0-SNAPSHOT`
+
+```
+dependencies {
+    compile 'org.cyanogenmod:platform.sdk:1.0-SNAPSHOT'
+}
+```
+
+Likewise, you can target the `future` or `development` branch by setting your `dependencies` for `2.0-SNAPSHOT`
+
+```
+dependencies {
+    compile 'org.cyanogenmod:platform.sdk:2.0-SNAPSHOT'
+}
+```
+
+### WIKI
+
+For further inquiries regarding this project, please reference the [wiki](https://github.com/CyanogenMod/cm_platform_sdk/wiki)