add base map for fatality data

app/server.R

@@ -1,4 +1,9 @@
 server <- function(input, output, session) {
+  output$base_leaflet <- renderLeaflet({
+    leaflet() %>%
+      addProviderTiles("Stadia.AlidadeSmooth")
+  })
+
   storm_coverage <- get_storm_data_coverage() %>%
     select(-storm_basin) %>%
     {