odoo 10 creating a group and associate it to a custom module
In real it's a fake problem because the field "Application" in the form corresponds to an Application category not Application (or module) so a users group (from the menu Setting -> Users -> Groups ) will be applied to a set of Applications (Modules) not for a unique application, so if anyone want to make a group for a unique module he could name the category attribute in the manifest file the as the same of the application (module name)
so try to get the category of your application and choose it from the list.
I've created a new module in odoo 10 with différents menus, now I want to create a user who have some menus of this module. So I created the user but when I tried to create the group (in order to associte to the groupe the menu) in the field application I can't find the module that I've created. I've  seted in the manifest file the field application to true and I've checked in the database in ir_module the field is true. Can someone help me please