README.md in trend-0.1.0 vs README.md in trend-0.1.1

@@ -1,18 +1,20 @@
 # Trend
 
-Ruby client for [Trend](https://trendapi.org), the time series API
+Ruby client for [Trend](https://trendapi.org), the anomaly detection and forecasting API
 
+[![Build Status](https://travis-ci.org/ankane/trend.svg?branch=master)](https://travis-ci.org/ankane/trend)
+
 ## Getting Started
 
 Add this line to your application’s Gemfile:
 
 ```ruby
 gem 'trend'
 ```
 
-### Anomalies
+### Anomaly Detection
 
 Detect anomalies in a time series
 
 ```ruby
 # generate series
@@ -34,11 +36,11 @@
 ```ruby
 series = User.group_by_day(:created_at).count
 Trend.anomalies(series)
 ```
 
-### Forecast
+### Forecasting
 
 Get future predictions for a time series
 
 ```ruby
 series = {}
@@ -60,9 +62,27 @@
 
 Specify the number of predictions to return
 
 ```ruby
 Trend.forecast(series, count: 3)
+```
+
+### Correlation [experimental]
+
+Get the correlation between two time series
+
+```ruby
+Trend.correlation(series, series2)
+```
+
+## Authentication
+
+An API key is needed for more than 1000 requests per day per IP. [Email us](mailto:[e-mail]) to get one.
+
+If you have one, set `ENV["TREND_API_KEY"]` or use:
+
+```ruby
+Trend.api_key = "secret"
 ```
 
 ## History
 
 View the [changelog](https://github.com/ankane/trend/blob/master/CHANGELOG.md)