Add a draft post on forward analysis

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>

content/blog/01_spa_agda_lattices.md

@@ -79,6 +79,7 @@ a less specific output! The more you know going in, the more you should know
 coming out. Similarly, when given less specific / vaguer information, the
 analysis shouldn't produce a more specific answer -- how could it do that?
 This leads us to come up with the following rule:
+{#define-monotonicity}
 
 {{< latex >}}
 \textbf{if}\ \text{input}_1 \le \text{input}_2,