change process.cwd to process.cwd() - closes #177

Author: stephenlacy

lib/add.js

@@ -11,7 +11,7 @@ module.exports = function (opt) {
 
   var paths = [];
   var files = [];
-  var fileCwd = process.cwd;
+  var fileCwd = process.cwd();
 
   var write = function(file, enc, cb) {
     paths.push(file.path);