included old BSON constant for deprecation warning

lib/mongo_bson.rb

@@ -3,9 +3,34 @@ $:.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
 module Mongo
   module BSON
     VERSION = "0.19.2"
+    def self.serialize(obj, check_keys=false, move_id=false)
+      warn "BSON has been deprecated. Use Mongo::BSON_CODER instead."
+      BSON_CODER.serialize(obj, check_keys, move_id)
+    end
+
+
+    def self.deserialize(buf=nil)
+      warn "BSON has been deprecated. Use Mongo::BSON_CODER instead."
+      BSON_CODER.deserialize(buf)
+    end
   end
 end
 
+# This just exists for deprecation warnings. Will be removed in an upcoming version.
+module BSON
+  def self.serialize(obj, check_keys=false, move_id=false)
+    warn "BSON has been deprecated. Use Mongo::BSON_CODER instead."
+    BSON_CODER.serialize(obj, check_keys, move_id)
+  end
+
+
+  def self.deserialize(buf=nil)
+    warn "BSON has been deprecated. Use Mongo::BSON_CODER instead."
+    BSON_CODER.deserialize(buf)
+  end
+end
+
+
 begin
   # Need this for running test with and without c ext in Ruby 1.9.
   raise LoadError if ENV['TEST_MODE'] && !ENV['C_EXT']

test/mongo_bson/bson_test.rb

@@ -22,6 +22,13 @@ class BSONTest < Test::Unit::TestCase
 
   include Mongo
 
+
+  def test_deprecated_bson_module
+    doc = {'doc' => 'hello, world'}
+    bson = BSON.serialize(doc)
+    assert_equal doc, BSON.deserialize(bson)
+  end
+
   def test_string
     doc = {'doc' => 'hello, world'}
     bson = bson = Mongo::BSON_CODER.serialize(doc)