Simplese model of "Post"
small simple to create post
Simplest POST API of posts
Format the output of GET posts API
Get single post
Optimize error handling
Delete post
Compile & docs
Globally set the charset of all responses to 'utf-8'
Refine POST model
Add PUT API for post model
Merge branch 'dev' into features/post
Limit the version of mongoose to prevent from installing a pre-release version
UT for post API & some fix according to UT result
Finish post (#6)
Merged 'dev'.

Conflicts:
	doc/index.html
temp