displays a message when a failure happen while creating a new category
site setting for category colors
Revert "update am serializer to latest with my perf fix"

turns out it is broken for now due to other am updates
Merge pull request #464 from ZogStriP/fix-issues-when-a-failure-happen-while-creating-a-new-category

displays a message when a failure happen while creating a new category
Merge pull request #483 from ZogStriP/site-setting-for-category-color

site setting for category colors
add missing translation for chinese
Update README.md

- bullet pointed the getting started guide
- added a reference to the Admin "How To" wiki page
- clarified the developer guide as adequate for beginners
For Evil Trout blog part 2: switch between bar chart and table
Merge pull request #485 from williamherry/add_missing_translation_for_chinese

add missing translation for chinese