feat: add PostgreSQL chapter, site generator & deploy

Add a new 18-database chapter (18-database/main.go) demonstrating PostgreSQL usage: connection pooling, DDL, CRUD, transactions, prepared statements, JSONB, JOINs and a Repository pattern. Add a Python static site generator (scripts/build-site.py) and a GitHub Actions workflow (.github/workflows/deploy-site.yml) to build and deploy the site to GitHub Pages. Update README to include the new chapter and add github.com/lib/pq to go.mod. Also add .gitignore entries for generated site and built binaries.

Author: Shelton Cheung

.github/workflows/deploy-site.yml

@@ -0,0 +1,49 @@
+name: Deploy Go Roadmap Site
+
+on:
+  push:
+    branches: [main, master]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.x'
+
+      - name: Build site
+        run: python scripts/build-site.py
+
+      - name: Setup Pages
+        uses: actions/configure-pages@v5
+
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: site
+
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

.gitignore

@@ -0,0 +1,21 @@
+# Build output
+site/
+
+# Go binaries
+01-getting-started/01-getting-started
+02-variables-constants/02-variables-constants
+03-data-types/03-data-types
+04-composite-types/04-composite-types
+05-control-flow/05-control-flow
+06-functions/06-functions
+07-pointers/07-pointers
+08-methods-interfaces/08-methods-interfaces
+09-generics/09-generics
+10-error-handling/10-error-handling
+11-modules-packages/11-modules-packages
+12-concurrency/12-concurrency
+13-standard-library/13-standard-library
+14-testing/14-testing
+15-ecosystem/15-ecosystem
+16-toolchain/16-toolchain
+17-advanced/17-advanced