Fix the link to the docs.

jbranchaud · jbranchaud · commit 2dd08e0f0b26 · 2015-12-26T16:08:27.000-06:00
diff --git a/postgres/two-ways-to-compute-factorial.md b/postgres/two-ways-to-compute-factorial.md
@@ -20,6 +20,6 @@ The postfix operator is `!` and can be used like so:
       120
 ```
 
-See the [arithmetic function
-docs](http://stackoverflow.com/questions/7866353/git-list-all-available-commands)
+See the [mathematical functions and operators
+docs](http://www.postgresql.org/docs/8.1/static/functions-math.html)
 for more details.

Original file line number	Diff line number	Diff line change
@@ -20,6 +20,6 @@ The postfix operator is `!` and can be used like so:
`20`	`20`	`120`
`21`	`21`	```
`22`	`22`
`23`		`-See the [arithmetic function`
`24`		`-docs](http://stackoverflow.com/questions/7866353/git-list-all-available-commands)`
	`23`	`+See the [mathematical functions and operators`
	`24`	`+docs](http://www.postgresql.org/docs/8.1/static/functions-math.html)`
`25`	`25`	`for more details.`