d Add Swift-specific readme

swift/README.md

@@ -0,0 +1,12 @@
+## Build and test using any of the following
+
+Command line:
+- `swift test`
+
+Xcode:
+- Open this "swift" folder to open package
+- In the Xcode menu, select Product > Test to run tests
+
+AppCode:
+- Open this "swift" folder to open package
+- Select "GildedRoseTests" configuration and run