add Hermes Broker by default & stub w/refer to installation instructions

tom_alerts/alerts.py

@@ -22,6 +22,7 @@
     'tom_alerts.brokers.antares.ANTARESBroker',
     'tom_alerts.brokers.gaia.GaiaBroker',
     'tom_alerts.brokers.fink.FinkBroker',
+    'tom_alerts.brokers.hermes.HermesBroker',
 ]
 
 

tom_alerts/brokers/hermes.py

@@ -0,0 +1,32 @@
+from crispy_forms.layout import Layout, HTML
+
+from tom_alerts.alerts import GenericBroker, GenericQueryForm, GenericAlert
+
+
+class HermesQueryForm(GenericQueryForm):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.helper.inputs.pop()
+        self.helper.layout = Layout(
+            HTML('''
+                <p>
+                This plugin is a stub for the Hermes Broker plugin. In order to install the full plugin, please see the
+                instructions <a href="https://github.com/TOMToolkit/tom_hermes">here</a>.
+                </p>
+            '''),
+            HTML('''<a class="btn btn-outline-primary" href={% url 'tom_alerts:list' %}>Back</a>''')
+        )
+
+
+class HermesBroker(GenericBroker):
+    name = 'Hermes'
+    form = HermesQueryForm
+
+    def fetch_alerts(self, parameters):
+        return iter([]), ''
+
+    def process_reduced_data(self, target, alert=None):
+        return
+
+    def to_generic_alert(self, alert):
+        return GenericAlert()