[CHORE] Add project description and goals to readme (#15)

[CHORE] Add project description and goals to readme

Author: Robert Jackson

README.md

@@ -3,3 +3,27 @@
 [![Build Status](https://travis-ci.com/ember-codemods/ember-codemods-telemetry-helpers.svg?branch=master)](https://travis-ci.com/ember-codemods/ember-codemods-telemetry-helpers)
 
 [![npm](https://img.shields.io/npm/v/ember-codemods-telemetry-helpers.svg?label=npm)](https://www.npmjs.com/package/ember-codemods-temetry-helpers)
+
+Telemetry helpers runs the app, grabs basic info about all of the modules at runtime. 
+This allows the codemod to know the names of every helper, component, route, controller, etc in the app without guessing / relying on static analysis.
+They basically help you to create "runtime assisted codemods".
+
+## Goal
+The goal of the project though was to enable each codemod to manage its own type of data gathering
+and that the gather-telemetry-helpers package provides the harness to run that custom gathering function
+
+## More info
+
+See "Gathering runtime data" section of 
+https://github.com/ember-codemods/ember-native-class-codemod#gathering-runtime-data for some additonal info
+
+
+This project was extracted from (ember-native-class-codemod)(https://github.com/ember-codemods/ember-native-class-codemod). 
+That codemod uses (puppeteer)(https://github.com/GoogleChrome/puppeteer) (via this lib) to visit the Ember app and gather telemetry necessary to convert to native classes. 
+
+The idea for the extraction was to put the harness in this package 
+(extracted from the native class codemod), but have the actual "telemetry gathering" 
+live in each individual codemod project because the things that they need are quite different
+for example, for [implicit this codemod](https://github.com/ember-codemods/ember-no-implicit-this-codemod) and 
+[angle brackets codemod](https://github.com/ember-codemods/ember-angle-brackets-codemod) all we need to know is an array of the helpers and components in the app
+but for [native class codemod](https://github.com/ember-codemods/ember-native-class-codemod) it needs much more info (names and types of methods, properties, etc on each default export)