create createGroup files

+type Mutation {
+  createGroup(name: String!): Group!
+}

+import { prisma, isAuthenticated } from "../../../utils";
+
+export default {
+  Mutation: {
+    createGroup: async (_, args, { request }) => {
+      isAuthenticated(request);
+      const { user } = request;
+      const { name } = args;
+
+      return prisma.group.create({
+        data: {
+          name,
+          creator: user,
+        },
+      });
+    },
+  },
+};