add example for input patterns

Author: lovasoa

examples/official-site/sqlpage/migrations/01_documentation.sql

@@ -264,6 +264,7 @@ When loading the page, the value for `:username` will be `NULL` if no value has
     '{"name": "Last name", "required": true, "description": "We need your last name for legal purposes."},'||
     '{"name": "Resume", "type": "textarea"},'||
     '{"name": "Birth date", "type": "date", "max": "2010-01-01", "value": "1994-04-16"},'||
+    '{"name": "Password", "type": "password", "pattern": "^(?=.*[A-Za-z])(?=.*\\d)[A-Za-z\\d]{8,}$", "required": true, "description": "Minimum eight characters, at least one letter and one number."},'||
     '{"label": "I accept the terms and conditions", "name": "terms", "type": "checkbox", "required": true}'||
     ']')),
     ('form', 'This example illustrates the use of the `select` type.