make sure geo_field is always included even when fields are explicitly specified
make sure geo_field is always included even when fields are explicitly specified

nmandery/django-rest-framework-gis,pglotov/django-rest-framework-gis,bopo/django-rest-framework-gis,manhg/django-rest-framework-gis,djangonauts/django-rest-framework-gis,illing2005/django-rest-framework-gis,nmandery/django-rest-framework-gis,arjenvrielink/django-rest-framework-gis,barseghyanartur/django-rest-framework-gis,sh4wn/django-rest-framework-gis