add automated tests in github ci

.github/workflows/ci.yml

@@ -0,0 +1,13 @@
+name: CI
+
+on: [push]
+
+jobs:
+  Test:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Extract example from README.md and run 
+      run: .github/workflows/test.sh

.github/workflows/test.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+set -ex
+
+cat README.md | sed -n '/```ini/,/```/p'  | grep -v '```' > config.ini
+
+cat > example.c <<EOF
+#include "src/ini.h"
+#include "stdio.h"
+#include "stddef.h"
+int main(){
+EOF
+cat README.md | sed -n '/```c/,/```/p'  | grep -v '```' >> example.c
+echo 'return 0;' >> example.c
+echo '}' >> example.c
+
+gcc example.c src/ini.c -o example ${CFLAGS} -Wall -Wextra -Werror
+
+./example