Shopify’s revenue grew 56% to $1 billion in the second quarter from the year earlier period, a sign of how the ecommerce software firm is benefiting from the surge in online shopping. Shopify’s operating income surged to $139 million from $284,000 a year earlier. Meanwhile, a $779 million unrealized net gain on investments lifted Shopify’s net income to $879 million, from $35 million a year...