add GH Actions CI (#18)

* add GH Actions CI

* add some badges to the README

* always force rebuilding in CI

.github/workflows/build_latex.yml

@@ -0,0 +1,22 @@
+name: Build LaTeX document
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+jobs:
+  build_latex:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Git repository
+        uses: actions/checkout@v2
+      - name: Compile LaTeX document
+        uses: xu-cheng/texlive-action/full@v1
+        with:
+          run: |
+            apk add make
+            make -B
+      - name: Upload Artifact
+        uses: actions/upload-artifact@v2
+        with:
+          name: PDF
+          path: main.pdf

README.md

@@ -1,5 +1,8 @@
 # Thesisvorlage für die Fakultät für Physik am KIT
 
+[![Build LaTeX document](https://github.com/fsphys/thesisvorlage-latex/actions/workflows/build_latex.yml/badge.svg)](https://github.com/fsphys/thesisvorlage-latex/actions/workflows/build_latex.yml)
+[![PDF Preview](https://img.shields.io/badge/docs-dev-blue.svg)](https://nightly.link/fsphys/thesisvorlage-latex/workflows/build_latex/master/PDF.zip)
+
 This thesis class is strongly related to the [Praktikumsvorlage](https://github.com/fsphys/praktikum-protokollvorlage-latex/).
 
 ## Use the template