Added experimental WSL gdk installation instructions

As per the title says, Added installation as well as some troubleshooting instructions for problems that I've encountered during the installation

cc @stanhu

doc/howto/troubleshooting.md

@@ -360,20 +360,10 @@ RAILS_ENV=test bundle exec rake db:reset
 * `gdk run db` fails with exit code X
-    If you have restarted your computer recently don't forget to start the postgresql service manually, init.d scripts don't currently as of build 15063.138
-
-    TL;DR
+    If you have restarted your computer recently, don't forget to start PostgreSQL server manually; init.d scripts don't work currently as of build 15063.138:
     `sudo service postgresql start`
-* `gdk run app` fails with gitaly error code XXX
-
-    Please run `gdk reconfigure`, note, this *might* happen during the initial run after the database has seeded
-
-* I get an EOF when accessing http://127.0.0.1:3000 instead of the sign up page
-
-    There's two possible solutions for this problem, make sure you have sufficient free RAM, otherwise just refresh the page.
-
 ## Other problems
 Please open an issue on the [GDK issue tracker](https://gitlab.com/gitlab-org/gitlab-development-kit/issues).