Ignore Visual Studio Code configuration

Since adding such configuration to the repository might not be
desirable, this configure Git to ignore it, to prevent it from being in
the way or accidentally committed.

Author: hannobraun

.gitignore

@@ -1,3 +1,6 @@
 /target
 **/*.rs.bk
 Cargo.lock
+
+# Visual Studio Code
+/.vscode