Initial MVP of GitHub gist support

lang/en-US.json

@@ -294,5 +294,8 @@
   "experiments": "Experiments",
   "experiments_notice": "This is a collection of experiments we're working on that might turn out to be useful, fun, both, or neither. They're not final and may not be stable, so if something overly weird happens, don't panic. Just turn the dang thing off. Jokes aside, ",
   "use_experimental_url_bar": "Use experimental URL bar with environment highlighting",
-  "select_environment": "Select environment"
+  "select_environment": "Select environment",
+  "login_with_github_to": "Login with GitHub to ",
+  "create_secret_gist": "Create secret Gist",
+  "gist_created": "Gist created"
 }