updated readme
updated readme

JackDougherty/leaflet-storymap,JackDougherty/leaflet-storymap,DataVizForAll/leaflet-storymaps-with-google-sheets,ignacioazzi/ignacioazzi.github.io,SteveBatt/leaflet-storymap,JackDougherty/leaflet-storymap-mapbox,shuxinzhang/leaflet-storymap,shuxinzhang/leaflet-storymap,DataVizForAll/leaflet-storymaps-with-google-sheets,SteveBatt/leaflet-storymap,ignacioazzi/ignacioazzi.github.io,JackDougherty/leaflet-storymap-mapbox