[server] Reimplement collaborative editing

forest-common/src/Forest/Node.hs

@@ -82,7 +82,7 @@ data Node = Node
   { nodeText     :: !T.Text
   , nodeFlags    :: !NodeFlags
   , nodeChildren :: !(OMap.OrderedMap NodeId Node)
-  } deriving (Show)
+  } deriving (Show, Eq)
 
 instance ToJSON Node where
   toJSON node = object

forest-common/src/Forest/OrderedMap.hs

@@ -65,7 +65,7 @@ import qualified Data.Set        as Set
 data OrderedMap k a = OrderedMap
   { omMap   :: Map.Map k a
   , omOrder :: [k]
-  }
+  } deriving (Eq)
 
 instance (Ord k, Show k, Show a) => Show (OrderedMap k a) where
   show m = "fromList " ++ show (toList m)