Added default backend value (#204)

* Update metadata.json

* Update metadata.json

* Update metadata.json

* Update TabTraining.vue

* Update metadata.json

Author: vfdev-5

src/components/TabTraining.vue

@@ -9,12 +9,12 @@
     <h2 class="training">Distributed Training</h2>
     <FormCheckbox label="Use distributed training" saveKey="use_dist" />
     <div v-show="store.config.use_dist">
-      <h2>Choose a Backend</h2>
       <FormSelect
         required
         :saveKey="backend.name"
         :label="backend.description"
         :options="backend.options"
+        :defaultV="backend.default"
       />
       <FormRadio :options="[launch, spawn]" saveKey="dist" defaultV="launch" />
       <FormInput

src/metadata/metadata.json

@@ -44,8 +44,10 @@
     },
     "backend": {
       "name": "backend",
-      "description": "Choose a Backend",
-      "options": ["NCCL", "Gloo"]
+      "type": "array",
+      "description": "Choose a backend",
+      "options": ["Nccl", "Gloo"],
+      "default": "Nccl"
     }
   },
   "handlers": {