added file widget to dev docs

dev-guide/index.md

@@ -175,6 +175,9 @@ Organization:
  - **[image](#image-widget)**
  - **[text](#text-widget)** 
 
+Special Widgets:
+ - **[file](#file-widget)**
+
 Example of adding a field to the schema. What ever order you place the items in the schema is the order they will be displayed in the resulting dialog.
 ```
 export default {
@@ -342,6 +345,20 @@ Allows for text to be added to the dialog with instructions or more sophisticate
     label: 'This is a custom text that can be used to show extra info about what particulart parts of the command are to be used.',
   }
 ```
+
+## file widget
+Allows for from the local file system to be selected and the contents be made avaiable to the feature. 
+```
+  {
+    type: 'file',
+    name: 'file',
+    label: 'Select File',
+
+  },
+```
+
+
+
 # paramsInfo tool tip information 
 The paramsInfo section is used to define a string that shows up when you mouse over a feature from the time line. You can pass in items defined in the schema and use them to form the string template for the tool top text. The tooltip text is displayed when mousing over the feature in the part history. 
 ```