Add installation and citation to readme (#103)

Author: raphaelsaavedra

README.md

@@ -10,4 +10,22 @@
 [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 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.
+ScoreDrivenModels.jl is a Julia package for modeling, forecasting, and simulating time series with score-driven models, also known as 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.
+
+## Installation
+
+This package is registered so you can simply `add` it using Julia's `Pkg` manager:
+```julia
+pkg> add StateSpaceModels
+```
+
+## Citing the package
+
+If you use ScoreDrivenModels.jl in your work, we kindly ask you to cite the package [paper](https://arxiv.org/abs/2008.05506):
+
+    @misc{bodin2020scoredrivenmodelsjl,
+    title={ScoreDrivenModels.jl: a Julia Package for Generalized Autoregressive Score Models},
+    author={Guilherme Bodin and Raphael Saavedra and Cristiano Fernandes and Alexandre Street},
+    year={2020},
+    eprint={2008.05506}
+    }