chore: modernize repo and add github ci

Author: mariotacke

.eslintignore

@@ -0,0 +1 @@
+input.js

.github/workflows/nodejs.yml

@@ -0,0 +1,26 @@
+name: build
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [8.x]
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - name: npm install, lint, and test
+      run: |
+        npm ci
+        npm run lint
+        npm test
+      env:
+        CI: true

.npmrc

@@ -1,5 +1,5 @@
 # Advent of Code 2018 - My Solutions
-[![Build Status](https://travis-ci.org/mariotacke/advent-of-code-2018.svg?branch=master)](https://travis-ci.org/mariotacke/advent-of-code-2018)
+[![Build Status](https://github.com/mariotacke/advent-of-code-2018/workflows/build/badge.svg)](https://github.com/mariotacke/advent-of-code-2018/actions)
 [![Dependency Status](https://img.shields.io/david/mariotacke/advent-of-code-2018.svg)](https://david-dm.org/mariotacke/advent-of-code-2018)
 [![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/mariotacke/advent-of-code-2018/master/LICENSE)