Updated Nimbus Roadmap (markdown)

Nimbus-Roadmap.md

@@ -76,6 +76,12 @@ tasks are specified in the same level of detail.
   - https://github.com/ethereum/wiki/wiki/JSON-RPC
 
 
+### Test suite
+  Sub-tasks:
+  - CI tests for all libraries
+  - Validate that the entire history of Ethereum can be executed by Nimbus
+  - Do we fit in a certain memory/compute budget?
+
 ### 7. Node discovery
 
   - https://github.com/ethereum/devp2p/blob/master/rlpx.md#node-discovery