Created readme file

README.md

+
+Overview
+--------
+
+[Reference_Detector_doc] (https://escalate.readthedocs.io/projects/g4e/en/latest/detector_naming.html)
+[g4e] (https://gitlab.com/eic/escalate/g4e)
+
+[DD4hep](https://github.com/AIDAsoft/DD4hep)
+This library makes  full detector simulation
+by providing a set of flexible **parameterized detectors**.
+[DD4hep_manual] (https://dd4hep.web.cern.ch/dd4hep/usermanuals/DD4hepManual/DD4hepManual.pdf)
+