Update README.md

README.md

 # Workload Manager
 
+On a single node run with 
+```bash
+mpirun -n 4 ./wkmgr.py date
+```
+
+or for multie nodes:
+```bash
+srun -n 4 ./wkmgr.py date
+```
+
+without loader replace `wkmgr.py` with `wkloader.py`.
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