Update changelog and readme

CHANGELOG.md

@@ -1,5 +1,9 @@
 ## v1.12 [unreleased]
 
+#### New Parsers
+
+- [form_urlencoded](/plugins/processors/form_urlencoded/README.md) - Contributed by @byonchev
+
 #### New Processors
 
 - [date](/plugins/processors/date/README.md) - Contributed by @influxdata

README.md

@@ -304,6 +304,7 @@ For documentation on the latest development code see the [documentation index][d
 - [Collectd](/plugins/parsers/collectd)
 - [CSV](/plugins/parsers/csv)
 - [Dropwizard](/plugins/parsers/dropwizard)
+- [FormUrlencoded](/plugins/parser/form_urlencoded)
 - [Graphite](/plugins/parsers/graphite)
 - [Grok](/plugins/parsers/grok)
 - [JSON](/plugins/parsers/json)