add sample map def

interface/map_def/test/mapdef.json

@@ -0,0 +1,18 @@
+{
+    "defn": [
+        {
+            "key": "{Description}",
+            "map": "y",
+            "flag": "g",
+            "field": "f20",
+            "regex": ".{1,20}",
+            "retain": "y"
+        }
+    ],
+    "name": "First 20",
+    "where": [
+        {}
+    ],
+    "function": "extract",
+    "description": "pull first 20 characters from description for mapping"
+}