Update readme

Author: fguillot

README.md

@@ -1,6 +1,8 @@
 OAuth2 Authentication
 =====================
 
+[![Build Status](https://travis-ci.org/kanboard/plugin-oauth2.svg?branch=master)](https://travis-ci.org/kanboard/plugin-oauth2)
+
 Generic OAuth2 authentication plugin.
 
 Author
@@ -29,3 +31,33 @@ Configuration
 -------------
 
 Go to the application settings > integrations > OAuth2 Authentication.
+
+### 1) Create a new application on the OAuth2 provider
+
+Go to the third-party authentication provider and add a new application. 
+Copy and paste the **Kanboard callback URL** and generate a new set of tokens.
+
+The third-party provider will returns a **Client ID** and a **Client Secret**.
+Copy those values in the Kanboard's settings.
+
+### 2) Configure the provider in Kanboard
+
+- **Client ID**: Unique ID that comes from the third-party provider
+- **Client Secret**: Unique token that comes from the third-party provider
+- **Authorize URL**: URL used for authorization
+- **Token URL**: URL used to get tokens from third-party provider
+- **User API URL**: URL used to fetch user profile after authentication
+- **Username Key**: Key used to fetch the username from the user API response
+- **Name Key**: Key used to fetch the full name
+- **Email Key**: Key used to fetch the user email
+- **User ID Key**: Key used to fetch the unique user ID
+
+Example for Github OAuth2:
+
+- **Authorize URL**: `https://github.com/login/oauth/authorize`
+- **Token URL**: `https://github.com/login/oauth/access_token`
+- **User API URL**: `https://api.github.com/user`
+- **Username Key**: `login`
+- **Name Key**: `name`
+- **Email Key**: `email`
+- **User ID Key**: `id`