README.rdoc in fluent-plugin-mongo-0.7.2 vs README.rdoc in fluent-plugin-mongo-0.7.3

@@ -1,8 +1,8 @@
-= MongoDB plugin for Fluentd
+= MongoDB plugin for {Fluentd}[http://github.com/fluent/fluentd]
 
-fluent-plugin-mongo provides input and output plugins for {Fluentd}[http://fluentd.org/].
+fluent-plugin-mongo provides input and output plugins for {Fluentd}[http://fluentd.org] ({GitHub}[http://github.com/fluent/fluentd])
 
 = Installation
 
 == Gems
 
@@ -196,9 +196,24 @@
       ...
     </match>
 
 Specified value is a comma separated keys(e.g. key1,key2,key3).
 This parameter is useful for excluding shard keys in shard environment.
+
+=== replace_dot_in_key_with and replace_dollar_in_key_with
+
+BSON records which include '.' or start with '$' are invalid and they will be stored as broken data to MongoDB. If you want to sanitize keys, you can use _replace_dot_in_key_with_ and _replace_dollar_in_key_with_.
+
+    <match forward.*>
+      ...
+      # replace '.' in keys with '__dot__'
+      replace_dot_in_key_with __dot__
+    
+      # replace '$' in keys with '__dollar__'
+      # Note: This replaces '$' only on first character
+      replace_dollar_in_key_with __dollar__
+      ...
+    </match>
 
 == Buffer size limitation
 
 Mongo plugin has the limitation of buffer size.
 Because MongoDB and mongo-ruby-driver checks the total object size at each insertion.