updated README file

cocotb_sim/README.md

@@ -0,0 +1,13 @@
+![example workflow](https://github.com/npatsiatzis/recirculation_mux/actions/workflows/regression.yml/badge.svg)
+![example workflow](https://github.com/npatsiatzis/recirculation_mux/actions/workflows/coverage.yml/badge.svg)
+
+### Recirculation MUX RTL implementation
+
+- solution for data bus synchronization
+- uses a toggle pulse synchronizer to transmit a pulse across clock domains
+- pulses controls the sampling of the data bus on the receiving (sink) domain
+- CoCoTB testbench for functional verification
+    - $ make
+- CoCoTB-test unit testing to exercise the CoCoTB tests across a range of values for the generic parameters
+    - $  SIM=ghdl pytest -n auto -o log_cli=True --junitxml=test-results.xml --cocotbxml=test-cocotb.xml
+