Add the Event.visibility field

This shows if the event is visible to anyone or just people who are invited.

The calendar view already respects this flag.

calsocial/models.py

@@ -103,6 +103,23 @@ class ResponseType(Enum):
         return Enum.__eq__(self, other)
 
 
+class EventVisibility(Enum):
+    """Enumeration for event visibility
+    """
+
+    #: The event is private, only attendees and people invited can see the details
+    private = 0
+
+    #: The event is public, anyone can see the details
+    public = 5
+
+
+EVENT_VISIBILITY_TRANSLATIONS = {
+    EventVisibility.private: _('Visible only to attendees'),
+    EventVisibility.public: _('Visible to everyone'),
+}
+
+
 class SettingsProxy:
     """Proxy object to get settings for a user
     """
@@ -399,6 +416,9 @@ class Event(db.Model):
     #: The description of the event
     description = db.Column(db.UnicodeText())
 
+    #: The visibility of the event
+    visibility = db.Column(db.Enum(EventVisibility), nullable=False)
+
     def __as_tz(self, timestamp, as_timezone=None):
         from pytz import timezone, utc