/nix/var/nix/db is not writable

[DamienCassou]

./melpa-stable-packages.sh --threads 4 --melpa ../melpa --output melpa-stable-package.nix shell-switcher
Preprocessing library emacs2nix-0.1.0.0...
In-place registering emacs2nix-0.1.0.0...
Preprocessing executable 'melpa2nix' for emacs2nix-0.1.0.0...
Running melpa2nix...
(BadPrefetchOutput,"")
PackageException "shell-switcher" (ProcessFailed "nix-prefetch-zip" ["--url","https://github.com/DamienCassou/shell-switcher/archive/2c5575ae859a82041a4bacd1793b844bfc24c34f.tar.gz","--name","shell-switcher-2c5575ae859a82041a4bacd1793b844bfc24c34f-src"] (Died 1 "  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current\n                                 Dload  Upload   Total   Spent    Left  Speed\n\r  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0\r  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0\r100   169    0   169    0     0    459      0 --:--:-- --:--:-- --:--:--   459\n\r100 22707  100 22707    0     0  27327      0 --:--:-- --:--:-- --:--:-- 27327\nhash is 0ia7sdip4hl27avckv3qpqgm3k4ynvp3xxq1cy53bqfzzx0gcria\nerror: Nix database directory \8216/nix/var/nix/db\8217 is not writable: Permission denied\n"))

this is with #13

[ttuegel]

Fixed in b1b3c2d.