don't fail if default config doesn't exist

lib/parse.go

@@ -36,16 +36,21 @@ func Parse(dest interface{}) {
 	if err != nil {
 		bail(1, "unable to parse cli args: %s", err)
 	}
+
+    var doc *Doc
+
 	f, err := os.Open(DefaultPath)
-	if err != nil {
-		bail(1, "unable to open moon config file at path %s: %s", DefaultPath, err)
-	}
+	if err == nil {
         defer f.Close()
-
-	doc, err := Read(f)
+        d, err := Read(f)
         if err != nil {
             bail(1, "unable to parse moon config file at path %s: %s", DefaultPath, err)
         }
+        doc = d
+	} else {
+        doc = &Doc{items: make(map[string]interface{})}
+    }
+
 
 	for k, v := range cliArgs {
 		doc.items[k] = v