Add sentence about scope of the project

Author: felixcremer

README.md

@@ -8,6 +8,8 @@
 
 This is the Julia package developed within the [FAIRSenDD project](https://github.com/EarthyScience/FAIRSenDD).
 
+The aim of this project is to provide a forest change detection algorithm in Julia. 
+
 ## Citation
 
 F. Cremer, M. Urbazaev, J. Cortés, J. Truckenbrodt, C. Schmullius and C. Thiel, "Potential of Recurrence Metrics from Sentinel-1 Time Series for Deforestation Mapping," in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 13, pp. 5233-5240, 2020, doi: [10.1109/JSTARS.2020.3019333](https://dx.doi.org/10.1109/JSTARS.2020.3019333).