allow _cassim as db name
diff --git a/src/fabric_db_create.erl b/src/fabric_db_create.erl
index 8b9d32a..644694f 100644
--- a/src/fabric_db_create.erl
+++ b/src/fabric_db_create.erl
@@ -49,6 +49,8 @@
             ok;
         nomatch when DbName =:= <<"_replicator">> ->
             ok;
+        nomatch when DbName =:= <<"_cassim">> ->
+            ok;
         nomatch ->
             {error, illegal_database_name}
         end