Add users with predictable username and password

to development seed.

db/fixtures/development/05_users.rb

@@ -13,4 +13,20 @@ Gitlab::Seeder.quiet do
       print 'F'
     end
   end
+
+  (1..5).each do |i|
+    begin
+      User.seed(:id, [
+        id: i + 10,
+        username: "user#{i}",
+        name: "User #{i}",
+        email: "user#{i}@example.com",
+        confirmed_at: DateTime.now,
+        password: '12345678'
+      ])
+      print '.'
+    rescue ActiveRecord::RecordNotSaved
+      print 'F'
+    end
+  end
 end