Shopify's stock has staged a huge rally over the past year.Shares of Shopify (SHOP -0.97%) soared after the e-commerce software company reported strong results and issued upbeat guidance, saying an expected tariff effect has not materialized.The stock is now up more than 40% year to date, and up over 180% during the past year, as of this writing.Strong results and upbeat outlookAfter issuing conservative guidance last quarter, Shopify was decidedly more upbeat this time around. Meanwhile, its second-quarter ...