Added BitDevsZambia in Lusaka, Zambia to cities.md (#196)

Author: 5atoshiNakamoto

cities.md

@@ -31,6 +31,7 @@ As a disclaimer, BitDevs NYC has no official associations with or oversight of t
 - [London](https://londonbitdevs.org/)
 - [Los Angeles](https://bitdevsla.org/)
 - [Louisville](https://loubitdevs.org/)
+- [Lusaka](https://BitDevsZambia.org/)
 - [Melbourne](https://melb.bitdevs.com.au/)
 - [Mexico City](https://cdmxbitdevs.org)
 - [Miami](https://miamibitdevs.org/)