Added readme

Author: viskin

README.md

@@ -1,9 +1,39 @@
-TODO
+# Problem
 
-# problem
+You want to test your Android Cordova application with [Travis](https://travis-ci.org/) (or any other CI solution).
+And your tests need permission to be granted on emulator.
+For example, permission to access device storage.
 
-# solution
+**cordova run** command cannot grant permissions. So you cannot run your tests.
 
-# usage
+If you use [cordova-paramedic](https://github.com/apache/cordova-paramedic), you also out of luck.
+
+# Solution
+
+Add adb-ci to your project:
 
     npm install adb-ci --save-dev
+
+After adding adb-ci, CI build will always run cordova in such a way that it installs your app on emulator with
+all required permissions granted.
+
+So your tests that require permissions will work.
+
+See [cordova-plugin-photo-library](https://github.com/terikon/cordova-plugin-photo-library) for example of usage of adb-ci.
+
+# How it works
+
+adb-ci adds wrapper to adb command inside your project that will be activated when adb runs, by any node tool.
+cordova is one of such tools. Actually, under the hood, crodova runs adb to install and run your app.
+
+The wrapper is installed in node_modules\.bin\adb. This ways, calls to adb will be redirected to adb-ci.
+
+Every call to adb will be passed through by wrapper as is, except **adb install** command.
+The wrapper will add -g parameter to **adb install** call, so installed app will have granted permissions
+(see [adb docs](https://developer.android.com/studio/command-line/adb.html) for details).
+
+- adb-ci will be activated only when CI environment variable is set, so it will not interfere with development machines.
+
+- ANDROID_HOME envrionment variable should be set for adb-ci to work.
+
+That's it. Hope it will be useful to someone.

adb-ci.js

@@ -2,7 +2,7 @@
 
 'use strict';
 
-const IS_CI = true; //process.env.CI;
+const IS_CI = process.env.CI;
 
 const original_location = `${process.env.ANDROID_HOME}/platform-tools/adb`;