Merge pull request #12 from guardian/add-multipath-to-readme

Add multipath verification to readme

README.md

@@ -1,19 +1,19 @@
 # Testing in Production (TiP) [![Maven Central](https://img.shields.io/maven-central/v/com.gu/tip_2.12.svg?label=latest%20release%20for%202.12)](https://maven-badges.herokuapp.com/maven-central/com.gu/tip_2.12) [![Build Status](https://travis-ci.org/guardian/tip.svg?branch=master)](https://travis-ci.org/guardian/tip)
 
-How to verify the most important user journey is not broken without writing a test?
+How to verify the most important user journeys are not broken without writing a single test?
 
-After a fresh deploy to production, TiP verifies regression has not been introduced into _Business Critical Path (BCP)_ by setting a label on the latest
-deployed pull request the first time a production user successfully completes the BCP.
+After a fresh deploy to production, TiP verifies regression has not been introduced into _Mission Critical Paths (MCP)_ by setting a label on the latest
+deployed pull request the first time production users successfully complete all MCPs.
 
 ![pr_label_example](https://cloud.githubusercontent.com/assets/13835317/24607798/534dbcfe-186b-11e7-836b-4d9a7dcae7d3.png)
 
-BCP is the answer to: _**"What is the single most important user journey in my product?"**_
+MCP is the answer to: _**"What user journey should never fail?"**_
 
 ## User Guide
 
 1. Add TiP library to your application's dependencies:
 ```
-libraryDependencies += "com.gu" %% "tip" % "0.1.1"
+libraryDependencies += "com.gu" %% "tip" % "0.2.0"
 ```
 
 2. [Create a GitHub label](https://help.github.com/articles/creating-and-editing-labels-for-issues-and-pull-requests/), for instance, a green label with name `Verified in PROD`:
@@ -30,19 +30,32 @@ tip {
   label = "Verified in PROD"
 }
 ``` 
-5. Place `Tip.verify()` call at the point in the source code where BCP is successfully completed, 
-for instance, at "Thank You" page, or "Confirmation" page.
 
-Here is an example real world PR that sets up TiP: https://github.com/guardian/identity-admin/pull/153
+5. Define your MCPs by creating a `tip.yaml` file, at the project base directory level, with the following format:
+```
+- name: Buy Subscription
+  description: User completes subscription purchase journey
+
+- name: Register Account
+  description: User completes account registration journey
+```
+
+Note that the names of MCPs must be unique.
 
-## How it Works?
+5. Place `Tip.verify("My_unique_MCP_name")` calls at the points in the source code where each MCP is successfully completed. 
 
-`Tip.verify()` call will send two HTTP requests to [GitHub API](https://developer.github.com/v3/):
+For example, given the above `tip.yaml` you could place `Tip.verify("Buy Subscription")` at _Payment Thank You_ page, and `Tip.verify("Register Account")` at _Registration Confirmation_ page.
+
+## How it works?
+
+When users successfully complete all the defined MCPs, then `Tip.verify()` call sends two HTTP requests to [GitHub API](https://developer.github.com/v3/):
 
   1. [GET request](https://developer.github.com/v3/repos/commits/#get-a-single-commit) to find out the identification number of the latest merged pull request,
   1. [POST request](https://developer.github.com/v3/issues/labels/#add-labels-to-an-issue) to actually add the label to the pull request
 
-TiP will do this only once - the first time user completes BCP. 
+TiP will do this only once - the first time users complete all MCPs. 
+
+TiP does not care how many users it took to complete all the MCPs, that is, they could all be completed by a single user or multiple users could complete different subsets of MCPs at different points in time.
 
 You can also use TiP if your web app is load balanced across multiple instances. In this case TiP will 
 trigger once per instance, thus if you have 3 instances, then GitHub API will be hit six times, however