Add form, url, template and view; no functionality yet

Note that the index page group button and the group selection within a work spec have a temporary display none to hide it so that it can be merged

ldvspec/lofardata/forms.py

 from django.core.exceptions import ValidationError
 
-from .models import WorkSpecification, DataProductFilter
+from .models import WorkSpecification, DataProductFilter, Group
 
-from django.forms import ModelForm
+from django.forms import ModelForm, CharField
 
 
 class WorkSpecificationForm(ModelForm):
@@ -30,14 +30,14 @@ class WorkSpecificationForm(ModelForm):
     class Meta:
         model = WorkSpecification
         fields = ['filters', 'selected_workflow', 'selected_workflow_tag', 'processing_site',
-                  'predecessor_specification', 'batch_size',
-                  'is_auto_submit']
+                  'predecessor_specification', 'batch_size', 'group', 'is_auto_submit']
         labels = {
             'selected_workflow': 'Selected workflow',
             'selected_workflow_tag': 'Workflow tag',
             'processing_site': 'Processing Site (ATDB)',
             'predecessor_specification': 'Predecessor',
             'batch_size': 'Files per task',
+            'group': 'Group',
             'is_auto_submit': 'Auto submit'
         }
         help_texts = {'selected_workflow': "The pipeline to run on the processing site.",
@@ -45,5 +45,27 @@ class WorkSpecificationForm(ModelForm):
                       'processing_site': "The ATDB processing site to run a specific workflow in.",
                       'predecessor_specification': "The related predecessor of the current work specification.",
                       'batch_size': "The number of files every task generated by this work specification should have. Example: 10 files in total can be split into 5 tasks of 2 files.",
+                      'group': "Include the work specification to a group. Note that it will inherit the group's processing site and workflow specifications.",
                       'is_auto_submit': "By checking this box, the work specification will be directly sent to the processing site and thus does not need inspection."
                       }
+
+
+class GroupForm(ModelForm):
+    obs_ids = CharField(label='SAS IDs',
+                        help_text="A list of SAS IDs separated with a comma. Example: 123, 456, 789",
+                        required=True)
+
+    class Meta:
+        model = Group
+        fields = ['name', 'selected_workflow', 'selected_workflow_tag', 'processing_site', 'obs_ids']
+        labels = {
+            'selected_workflow': 'Selected workflow',
+            'selected_workflow_tag': 'Workflow tag',
+            'processing_site': 'Processing Site (ATDB)',
+            'name': 'Name',
+        }
+        help_texts = {'selected_workflow': "The pipeline to run on the processing site.",
+                      'selected_workflow_tag': "The pipeline's tag as specified in ATDB.",
+                      'processing_site': "The ATDB processing site to run a specific workflow in.",
+                      'name': "A unique and custom name for this group"
+                      }

[Robbie Luijben]

separated by just comma is fine? (there could be a space, or multiple, or none..)