add minimal README

Signed-off-by: Csaba Kiraly <csaba.kiraly@gmail.com>

README-DAS.md

@@ -0,0 +1,26 @@
+# DAS emulator
+
+Emulate DAS DHT behavior, with a few simple assumption
+- the block is populated in the DHT by the builder (node 0)
+- all nodes start sampling at the same time
+- 1-way latency is 50ms (configurable)
+- no losses in transmission (configurable)
+- scaled down numbers (nodes, blocksize, etc., all configrable)
+
+## Compilation
+
+```
+# install Nim 1.6
+
+# install Nimble 0.14+
+nimble install nimble
+
+# make sure the newly installed nimble is used
+export PATH=~/.nimble/bin:$PATH
+
+# install dependencies
+nimble install 
+
+# compile and run passing on various flags
+nimble run "-d:chronicles_sinks=textlines[stdout,nocolors]" -d:chronicles_log_level=INFO -d:release -d:asyncTimer=virtual das
+```