add createUser mutation

app/graphql/inputs/user_attributes_input.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+module Inputs
+  class UserAttributesInput < Types::BaseInputObject
+    graphql_name "UserAttributesInput"
+
+    argument :first_name, String, required: true
+    argument :last_name, String, required: true
+  end
+end

app/graphql/mutations/base_mutation.rb

@@ -5,5 +5,9 @@ module Mutations
     field_class Types::BaseField
     input_object_class Types::BaseInputObject
     object_class Types::BaseObject
+
+    field :errors, [String],
+      null: true,
+      description: "Errors encountered during execution of the mutation."
   end
 end

app/graphql/mutations/create_user.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+module Mutations
+  class CreateUser < BaseMutation
+    field :success, Boolean, null: false
+
+    argument :user, Inputs::UserAttributesInput, required: true
+
+    def resolve(user:)
+      User.create!({ **user, email: context[:current_auth].email })
+
+      { success: true }
+    rescue ActiveRecord::RecordInvalid => e
+      { success: false, errors: [e.message] }
+    end
+  end
+end

app/graphql/types/mutation_type.rb

@@ -1,11 +1,6 @@
 # frozen_string_literal: true
 module Types
   class MutationType < Types::BaseObject
-    # TODO: remove me
-    field :test_field, String, null: false,
-      description: "An example field added by the generator"
-    def test_field
-      "Hello World"
-    end
+    field :create_user, mutation: Mutations::CreateUser
   end
 end