Use city boundaries instead of city point

[MBoustani]

Currently data source is world cities point dataset and Georeverse calculate distance between given point and all cities point data. This could be end up to wrong result as closeness to city center is not always accurate.
Instead, finding if given point is located in city boundaries would be more accurate result.
For that we need all cities boundaries in any format such as shapefile or geojson, and use GDAL library to find whether point is located in polygon or not.