Use full text index for search_names

[maxpoletaev]

Using db_index for search_names is bad way. You should create full text index, not btree. Currently when importing geo data with many languages I get the error:

django.db.utils.OperationalError: index row size 4016 exceeds maximum 2712 for index "geo_city_610a2ab0"
HINT:  Values larger than 1/3 of a buffer page cannot be indexed.
Consider a function index of an MD5 hash of the value, or use full text indexing.

[jpic]

Accepted, open for PR.

[max-arnold]

Upcoming Django 1.10 can help: https://docs.djangoproject.com/en/dev/ref/contrib/postgres/search/

[eracle]

Django 3.1.13; postgis 13; django-cities-light 3.9.0.

Solved by putting this in Django settings: CITIES_LIGHT_INDEX_SEARCH_NAMES = False