Add model for counters

lib/GuestbookNg/Model/Counter.pm

@@ -0,0 +1,32 @@
+#!/usr/bin/env perl
+
+package GuestbookNg::Model::Counter;
+
+use Mojo::Base -base, -signatures;
+
+has 'pg';
+
+sub new($class, $pg, $pg_object) {
+    bless {
+        $pg       => $pg_object,
+        max_posts => 5
+    }
+}
+
+sub get_visitor_count($self) {
+    $self->pg->db->query(<<~'END_SQL')->text()
+        SELECT visitor_counter
+          FROM counters
+         WHERE counter_id = 1;
+       END_SQL
+}
+
+sub increment_visitor_count($self) {
+    $self->pg->db->query(<<~'END_SQL')->text()
+        UPDATE counters
+           SET visitor_counter = visitor_counter + 1
+         WHERE counter_id = 1;
+       END_SQL
+}
+
+1;