handle unsupported file types

app/javascript/template_builder/upload.vue

@@ -33,7 +33,7 @@
         ref="input"
         name="files[]"
         type="file"
-        accept="image/*, application/pdf"
+        :accept="acceptFileTypes"
         multiple
         @change="upload"
       >
@@ -56,6 +56,11 @@ export default {
       type: [Number, String],
       required: true
     },
+    acceptFileTypes: {
+      type: String,
+      required: false,
+      default: 'image/*, application/pdf'
+    },
     isDirectUpload: {
       type: Boolean,
       required: true,