feat: create_newtype_text

schema/000_newtype.sql

@@ -0,0 +1,16 @@
+create function create_newtype_text(qualified_name text)
+  returns void
+  language plpgsql
+  as $$
+begin
+  execute concat('create type ', qualified_name, ' as (str text);');
+  execute concat( 'create function '
+                , qualified_name || '_to_string(val ' || qualified_name || ')'
+                , E' returns text language sql as \'select (val.str);\';'
+                );
+  execute concat( 'create function '
+                , qualified_name || '_of_string(val text)'
+                , ' returns ' || qualified_name || E' language sql as \'select row(val);\';'
+                );
+end;
+$$;

schema/020_user.sql

@@ -1,4 +1,4 @@
-create type public.usr_username as (username text);
+select create_newtype_text('public.usr_username');
 
 create table public.usr_audit
   ( usr           int                 not null