start customer auth & signup

framework/shopify/utils/mutations/customer-create.ts

@@ -0,0 +1,15 @@
+const customerCreateMutation = /* GraphQL */ `
+  mutation customerCreate($input: CustomerCreateInput!) {
+    customerCreate(input: $input) {
+      customerUserErrors {
+        code
+        field
+        message
+      }
+      customer {
+        id
+      }
+    }
+  }
+`
+export default customerCreateMutation