Add the Response model

This is to store RSVPs.

calsocial/models.py

@@ -103,6 +103,24 @@ class ResponseType(Enum):
         return Enum.__eq__(self, other)
 
 
+class EventAvailability(Enum):
+    free = 0
+    busy = 1
+
+
+class UserAvailability(EventAvailability):
+    tentative = 2
+
+
+class ResponseVisibility(Enum):
+    private = 0
+    organisers = 1
+    attendees = 2
+    followers = 3
+    friends = 4
+    public = 5
+
+
 class SettingsProxy:
     """Proxy object to get settings for a user
     """
@@ -310,21 +328,6 @@ class Profile(db.Model):  # pylint: disable=too-few-public-methods
             .filter(UserFollow.followed == self) \
             .filter(UserFollow.accepted_at.isnot(None))
 
-    @property
-    def friend_list(self):
-        """List of friends (ie. where both profiles follow each other)
-        """
-
-        # This will always be empty for remote profiles
-        if not self.user:
-            return []
-
-        reverse = db.aliased(UserFollow)
-        return UserFollow.query \
-                         .filter(UserFollow.follower == self) \
-                         .join(reverse, UserFollow.followed == reverse.follower) \
-                         .filter(UserFollow.follower == reverse.followed)
-
     @property
     def url(self):
         """Get the URL for this profile