Odoo 11 CE depends on the module: res. But this module is not available in your system - odoo-11

Question

I'm currently using Odoo 11 CE and developing an app that would add some fields to res.partner. After looking at all the different samples out there I can't figure out why I get this error when upgrading:
You try to upgrade the module training_center that depends on the
module: res. But this module is not available in your system.
In my manifest file I've got the following:
manifest.py
'name': 'Training Center',
'author': 'Matt',
'website': 'tbd',
'depends': ['base','board', 'document', 'hr', 'web', 'website',
],
In my models directory I've got the following:
init.py
from . import res_partner
In my res_partner.py file I've got the following:
from odoo import models, fields, api, _
from odoo.exceptions import ValidationError
class TC_ResPartner(models.Model):
"""Adds wechat field becomes a stored function field."""
_inherit = 'res.partner'
wechat_id = fields.Char(
"Wechat User ID",
index=True,
store=True
)
When I go to upgrade in the UI via the APPS/Upgrade button, I get the following error:
You try to upgrade the module training_center that depends
on the module: res. But this module is not available in your system.
When I look in the server log, I see the following worth noting:
2018-12-08 16:12:03,313 27437 INFO odoo odoo.addons.base.module.module: ALLOW access to module.button_immediate_upgrade on ['training_center'] to user m****#gmail.com #7 via 127.0.0.1
2018-12-08 16:12:03,313 27437 INFO odoo odoo.addons.base.module.module: ALLOW access to module.button_upgrade on ['training_center'] to user m****#gmail.com #7 via 127.0.0.1
2018-12-08 16:12:03,313 27437 INFO odoo odoo.addons.base.module.module: ALLOW access to module.update_list on ['training_center'] to user m****#gmail.com #7 via 127.0.0.1
I've not had any permission issues with upgrading until I tried inheriting res.partner.
What am I missing?