LRDOCS-640: Added Indexer Post Processor Hook section and exercise
LRDOCS-640: Extend base impl instead of implementing interface
LRDOCS-640: Modify title
LRDOCS-640: Forgot to edit transition
Merge branch 'indexer-pp-hook' of https://github.com/codyhoag/liferay-docs into indexer-pp-hook
Merge pull request #780 from jhinkey/indexer-pp-hook

Indexer Post Processor Hook