Merge pull request #50 from shimwell/patch-1

Author: gonuke

README.md

@@ -23,7 +23,7 @@ Code:
 ```python
 import pydagmc
 
-model = pydagmc.DAGModel('dagmc.h5m')
+model = pydagmc.Model('dagmc.h5m')
 
 group_dict = model.groups_by_name
 print(group_dict)
@@ -82,4 +82,4 @@ Volume IDs:
 Group 0, Name: mat:41
 Volume IDs:
 [1 3]
-```
+```