Add GitHub Actions CI workflow (Makefile)

.github/workflows/build.yml

@@ -0,0 +1,21 @@
+name: C++ CI (Make)
+
+on:
+  push:
+    branches: [ "main", "ci/cd" ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install toolchain
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y build-essential
+
+      - name: Build (Makefile)
+        run: |
+          make -j"$(nproc)"

README.md

@@ -2,6 +2,9 @@
 
 This is a basic Docker container for a C++ program
 
+
+[![C++ CI (Make)](https://github.com/jgonzalez98-software/cpp-container/actions/workflows/build.yml/badge.svg)](https://github.com/jgonzalez98-software/cpp-container/actions/workflows/build.yml)
+
 ## Getting Started
 
 Build the image from `Dockerfile` with the command: