Add basic nix development shell (#9162)

* Add basic nix development shell

* Use google-chrome instead of chromium

* Move nix stuff to subdirectory

* Update gemset, improve readme, fix shell

* Update nix README, remove .envrc

.gitignore

@@ -114,3 +114,6 @@ structure.sql
 
 # Local development docker 
 /.env
+
+# Local development direnv file
+/.envrc

nix/README.md

@@ -0,0 +1,24 @@
+# Nix development
+
+This directory contains files that ease development on nix-enabled systems. Just run `nix-shell ./nix` in the root project directory.
+
+The setup was tested on docker-enabled systems, however nothing should stop you from using this without docker.
+
+This is still a work in progress, feel free to improve as needed.
+
+## Updating gemset.nix
+
+Run `bundix --gemset=./nix/gemset.nix` to update the gemset file from the Gemlock file.
+
+## Autoloading
+
+If you have `lorri` and `direnv` installed, you can autoload the shell by adding a `.envrc` to the root directory with
+the following contents: 
+
+```
+eval "$(lorri direnv --shell-file ./nix/shell.nix)"
+```
+
+## Questions?
+
+Contact @b12f