diff --git a/src/content/_templates/_post.md b/src/content/_templates/_post.md
new file mode 100644
index 0000000..5584602
--- /dev/null
+++ b/src/content/_templates/_post.md
@@ -0,0 +1,4 @@
+---
+title: Title
+date: {{date:YYYY-MM-DDTHH:mm:ssZ}}
+---
\ No newline at end of file
diff --git a/src/content/posts/category-theory.md b/src/content/posts/category-theory.md
new file mode 100644
index 0000000..35a1581
--- /dev/null
+++ b/src/content/posts/category-theory.md
@@ -0,0 +1,16 @@
+---
+title: Category theory, abstract algebra and friends
+date: 2023-05-14T21:57:54+02:00
+---
+
+## Monoid
+
+$$
+(M, *)
+$$
+
+```haskell
+class Monoid a where
+  mempty :: a
+  mappend :: a -> a -> a
+```
\ No newline at end of file