add CI workflow

.github/workflow/ci.yml

@@ -0,0 +1,46 @@
+name: CI for speedy.f90
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      # Step 1: Checkout the repository code
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      # Step 2: Install dependencies (gfortran, openmp, netcdf-fortran)
+      - name: Install gfortran, OpenMP, and netcdf-fortran
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y gfortran libnetcdff-dev
+
+      # Step 3: Set the NETCDF environment variable 
+      - name: Set NETCDF environment variable
+        run: echo "NETCDF=$(nc-config --prefix)" >> $GITHUB_ENV
+
+      # Step 4: Compile the project
+      - name: Compile the Fortran project
+        run: |
+          export NETCDF=$(nc-config --prefix)
+          bash build.sh --target general | tee compile.out
+
+      # Step 5: Check for compilation
+      - name: Check for compilation
+        run: |
+          if ! grep -q "successful" compile.out; then
+            echo "Compilation failed."
+            cat compile.out
+            exit 1  # Fail the action
+          else
+            echo "Compilation successful."
+          fi
+