Barebones Hostels App and CMSPlugin:

hostels.admin.py

# -*- coding: utf-8 -*-

from __future__ import unicode_literals

from django.contrib import admin

from .models import Hostel, Room


class RoomInlineAdmin(admin.TabularInline):
    model = Room


class HostelAdmin(admin.ModelAdmin):
    inlines = (RoomInlineAdmin, )

admin.site.register(Hostel, HostelAdmin)

hostels.cms_plugins.py

# -*- coding: utf-8 -*-

from __future__ import unicode_literals

from cms.plugin_base import CMSPluginBase
from cms.plugin_pool import plugin_pool

from .models import HostelPluginModel


class HostelPlugin(CMSPluginBase):
    model = HostelPluginModel
    name = 'Hostel rooms'
    render_template = 'hostels/plugins/hostel_rooms.html'

plugin_pool.register_plugin(HostelPlugin)

hostels.models.py

# -*- coding: utf-8 -*-

from __future__ import unicode_literals

from django.db import models
from django.utils.encoding import python_2_unicode_compatible

from cms.models import CMSPlugin


@python_2_unicode_compatible
class Hostel(models.Model):
    name = models.CharField(max_length=64)

    def __str__(self):
        return self.name


@python_2_unicode_compatible
class Room(models.Model):
    name = models.CharField(max_length=64)
    hostle = models.ForeignKey(Hostel, related_name="rooms")

    def __str__(self):
        return self.name


@python_2_unicode_compatible
class HostelPluginModel(CMSPlugin):
    hostel = models.ForeignKey(Hostel)

    def __str__(self):
        return "Rooms for hostel {0}".format(self.hostel)

hostels.templates.hostels.plugins.hostel_rooms.html

<h1>{{ instance.hostel.name }}</h1>
<ul>
    {% for room in instance.hostel.rooms.all %}
        <li>{{ room.name }}</li>
    {% empty %}
        <li>No rooms defined.</li>
    {% endfor %}
</ul>

What is possible way to pull data from Db and show in setting fields? Right now I am doing this:

MY_CHOICES = (
        ('a', 'Cat1'),
        ('b', 'Cat2'),
    )
    categories = models.CharField("Survey", help_text="Select Survey", choices=MY_CHOICES, max_length=3, blank=True)

How CHOICES can get data from Db and show in Combo?