Capitalize background scripts

src/background/domains/CompletionGroup.js

@@ -0,0 +1,14 @@
+export default class CompletionGroup {
+  constructor(name, items) {
+    this.name0 = name;
+    this.items0 = items;
+  }
+
+  get name() {
+    return this.name0;
+  }
+
+  get items() {
+    return this.items0;
+  }
+}