twitter: add field for mentions output channel

this removes an old, general field, which was once used for multiple
things, but we should break apart its functional usage and also just
refer to our IrcChannel object anyway

this is the easy half of issue #3

dr_botzo/twitter/migrations/0004_add_mentions_output_channel_to_config.py

@@ -0,0 +1,24 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('ircbot', '0014_auto_20160116_1955'),
+        ('twitter', '0003_auto_20150620_0951'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='twitterclient',
+            name='output_channel',
+        ),
+        migrations.AddField(
+            model_name='twitterclient',
+            name='mentions_output_channel',
+            field=models.ForeignKey(blank=True, related_name='mentions_twitter_client', null=True, to='ircbot.IrcChannel', default=None),
+        ),
+    ]

dr_botzo/twitter/models.py

@@ -4,6 +4,8 @@ import logging
 
 from django.db import models
 
+from ircbot.models import IrcChannel
+
 
 log = logging.getLogger('twitter.models')
 
@@ -13,10 +15,12 @@ class TwitterClient(models.Model):
     """Track twitter settings and similar."""
 
     since_id = models.PositiveIntegerField()
-    output_channel = models.CharField(max_length=200, default='', blank=True)
     oauth_token = models.CharField(max_length=256, default='', blank=True)
     oauth_token_secret = models.CharField(max_length=256, default='', blank=True)
 
+    mentions_output_channel = models.ForeignKey(IrcChannel, related_name='mentions_twitter_client', default=None,
+                                                null=True, blank=True)
+
     class Meta:
         permissions = (
             ('send_tweets', "Can send tweets via IRC"),