Add docs page on setting up Linux for Gatsby (#4716)

* new page an title

* add in outline

* build tools

* node-install

* links and preamble

* debian too

* Update gatsby-on-linux.md

* Copy edits

* Copy edits

* Update gatsby-on-linux.md

docs/docs/gatsby-on-linux.md

@@ -0,0 +1,69 @@
+---
+title: Gatsby on Linux
+---
+# Linux
+
+TODO
+
+## Windows Subsystem Linux (WSL)
+
+As of October 17th 2017, Windows 10 ships with WSL and Linux distributions are available via the [Windows Store], there are several different distributions to use which can be configured via `wslconfig` if you have more than one distribution installed.
+
+```sh
+# set default distribution to Ubuntu
+wslconfig /setdefault ubuntu
+```
+
+### Using Windows Subsystem Linux: Ubuntu
+
+If you have a fresh install of Ubuntu then update and upgrade:
+
+```sh
+sudo apt update
+sudo apt -y upgrade
+```
+
+>Only use `-y` if you're happy to upgrade to the latest versions of the software.
+
+**Build tools**
+
+To compile and install native addons from npm you may also need to install build tools for `node-gyp`:
+
+```sh
+sudo apt install -y build-essential
+```
+
+**Install node**
+
+Following the install instructions on nodejs.org leaves a slightly broken install (i.e. permission errors when trying to `npm install`). Instead try installing node versions using [n] which you can install with [n-install]:
+
+```sh
+curl -L https://git.io/n-install | bash
+```
+
+There are other alternatives for managing you node versions such as [nvm] but this is known to slow down [bash startup] on WSL.
+
+### Using Windows Subsystem Linux: Debian
+
+Debian setup is nearly identical to Ubuntu except for the additional installs of `git` and `libpng-dev`.
+
+```sh
+sudo apt update
+sudo apt -y upgrade
+sudo apt install build-essential
+sudo apt install git
+sudo apt install libpng-dev
+```
+
+Or to install all at the same time and approve (y) all installs:
+
+```sh
+sudo apt update && sudo apt -y upgrade && sudo apt install build-essential && sudo apt install git && sudo apt install libpng-dev
+```
+
+<!-- links -->
+[windows store]: https://www.microsoft.com/en-us/store/p/ubuntu/9nblggh4msv6
+[n]: https://github.com/tj/n
+[n-install]: https://github.com/mklement0/n-install
+[nvm]: https://github.com/creationix/nvm
+[bash startup]: https://github.com/Microsoft/WSL/issues/776#issuecomment-266112578