Add coordinates autocomplete widget & data (#32)

Just tweaks based on what Carl had already written in dce53630 and b97d421a

apps/map/forms.py

@@ -2,12 +2,14 @@ from django.urls import reverse
 from django import forms
 from django.utils.translation import ugettext as _
 from django.utils.safestring import mark_safe
+
 from crispy_forms.helper import FormHelper
 from crispy_forms.layout import Submit, Layout, HTML, Fieldset, Div
 from crispy_forms.bootstrap import Tab, TabHolder, PrependedText, FormActions
+from dal import autocomplete
 from leaflet.forms.widgets import LeafletWidget
 
-from .models import CaseStudy
+from .models import CaseStudy, SpatialRefSys
 
 
 class MinimumZoomWidget(LeafletWidget):
@@ -80,6 +82,12 @@ class ShortCaseStudyForm(BaseCaseStudyForm):
 class LongCaseStudyForm(BaseCaseStudyForm):
     """Long version of the CaseStudy form."""
 
+    coordinate_reference_system = forms.ModelChoiceField(
+        queryset=SpatialRefSys.objects.all(),
+        widget=autocomplete.ModelSelect2(url='srs-autocomplete'),
+        initial=4326,
+    )
+
     POSITIVE_CASE_TYPE_HELP = {
         'CREP': _("We are using the World Wind Energy Association's Community Power definition, \
                    which is that a community project is one where at least \