Add a bit more explanation to the latest til

Author: jbranchaud

postgres/set-seed-for-random-number-generator.md

@@ -6,6 +6,10 @@ particular seed in order to get some determinism from functions that utilize
 the random number generator. The seed needs to be something between `0` and
 `1`.
 
+We can see this in action by setting the seed and then invoking `random()` a
+couple times. Doing this twice, we will see the reproducibility we can
+achieve with a seed.
+
 ```sql
 > set seed to 0.1234;
 SET