Add GitHub Actions using cachix (#232)

* Add GitHub Actions using cachix

* Update meta

.github/workflows/build.yml

@@ -0,0 +1,15 @@
+name: "tomland: nix + cachix"
+on:
+  pull_request:
+  push:
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v1
+    - uses: cachix/install-nix-action@v3
+    - uses: cachix/cachix-action@v2
+      with:
+        name: kowainik
+        signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
+

.gitignore

@@ -26,6 +26,9 @@ cabal.project.local
 .stack-work/
 stack.yaml.lock
 
+# Nix
+result
+
 ### IDE/support
 # Vim
 [._]*.s[a-v][a-z]

README.md

@@ -1,6 +1,7 @@
 # tomland
 
 ![palm](https://user-images.githubusercontent.com/4276606/51088259-7a777000-176e-11e9-9d76-6be4023c0ac3.png)
+[![GitHub actions](https://github.com/actions/kowainik/tomland/.github/workflows/build.yml/badge.svg)](https://github.com/kowainik/tomland/actions)
 [![Build status](https://img.shields.io/travis/kowainik/tomland.svg?logo=travis)](https://travis-ci.org/kowainik/tomland)
 [![Hackage](https://img.shields.io/hackage/v/tomland.svg?logo=haskell)](https://hackage.haskell.org/package/tomland)
 [![Stackage LTS](http://stackage.org/package/tomland/badge/lts)](http://stackage.org/lts/package/tomland)

default.nix

@@ -0,0 +1,5 @@
+{ pkgs ? import <nixpkgs> {}
+}:
+pkgs.haskellPackages.developPackage {
+  root = ./.;
+}