fix alerts with conditions

rowers/alerts.py

@@ -93,7 +93,7 @@ def alert_get_stats(alert, nperiod=0):  # pragma: no cover
     columns = [alert.measured.metric]
 
     for condition in alert.filter.all():
-        columns += condition.metric
+        columns.append(condition.metric)
 
     workouts = Workout.objects.filter(date__gte=startdate, date__lte=enddate, user=alert.rower,
                                       workouttype=alert.workouttype, duplicate=False,

rowers/models.py

@@ -1377,6 +1377,16 @@ class Condition(models.Model):
     condition = models.CharField(
         max_length=20, choices=conditionchoices, null=True)
 
+    def __str__(self):
+        str = 'Condition: {metric} {condition} {value1} {value2}'.format(
+            metric=self.metric,
+            condition=self.condition,
+            value1 = self.value1,
+            value2 = self.value2,
+        )
+
+        return str
+
 
 class ConditionEditForm(ModelForm):
     class Meta: