Add `MathJax` support (#43)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

README.md

@@ -15,6 +15,22 @@ To add a new blogpost, please refer to `_posts/2023-06-20-vllm.md` as an example
 
 The blog is automatically built and deployed by GitHub Actions when `main` is pushed to.
 
+## LaTeX Math
+
+The blog supports LaTeX math via [MathJax](https://docs.mathjax.org/en/latest/index.html). 
+
+It can be enabled by adding `math: true` to the document frontmatter. It has been configured to support the standard LaTeX style math notation, i.e.:
+
+```latex
+$ inline math $
+```
+
+```latex
+$$
+math block
+$$
+```
+
 ## Theme customization
 
 The theme we are using is [Minima](https://github.com/jekyll/minima). If you need to customise anything from this theme, see [Overriding theme defaults](https://jekyllrb.com/docs/themes/#overriding-theme-defaults).

_includes/custom-head.html

@@ -0,0 +1,12 @@
+{% if page.math %}
+<script>
+    MathJax = {
+        tex: {
+            inlineMath: [['$', '$'], ['\\(', '\\)']],
+            displayMath: [['$$', '$$'], ['\\[', '\\]']]
+        }
+    };
+</script>
+<script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-chtml.js">
+</script>
+{% endif %}