add badges to readme (#27)

Author: raphaelsaavedra

README.md

@@ -1,5 +1,15 @@
 # ScoreDrivenModels.jl
 
+| **Build Status** | **Coverage** | **Documentation** |
+|:-----------------:|:-----------------:|:-----------------:|
+| [![Build Status][build-img]][build-url] | [![Codecov branch][codecov-img]][codecov-url] |[![](https://img.shields.io/badge/docs-latest-blue.svg)](https://lampspuc.github.io/ScoreDrivenModels.jl/latest/)
+
+[build-img]: https://travis-ci.org/LAMPSPUC/ScoreDrivenModels.jl.svg?branch=master
+[build-url]: https://travis-ci.org/LAMPSPUC/ScoreDrivenModels.jl
+
+[codecov-img]: https://codecov.io/gh/LAMPSPUC/ScoreDrivenModels.jl/coverage.svg?branch=master
+[codecov-url]: https://codecov.io/gh/LAMPSPUC/ScoreDrivenModels.jl?branch=master
+
 ScoreDrivenModels.jl is a Julia package for modeling, forecasting and simulating time series with score-driven models, also known as dynamic conditional score models (DCS) or generalized autoregressive score models (GAS). Implementations are based on the paper [Generalized Autoregressive Models with Applications](http://dx.doi.org/10.1002/jae.1279) by D. Creal, S. J. Koopman and A. Lucas.
 
 # Features
@@ -15,4 +25,4 @@ ScoreDrivenModels.jl is a Julia package for modeling, forecasting and simulating
 
 # Roadmap
 * Weibull distribution
-* Unobserved components structure
+* Unobserved components structure