Create Post Template

Another step

Tonight I create a post template. It's not a easy task. I was quite confused about the usage of jekyll. I thought some of the features were out of work. Then I took a gander with other blogs and their source. It is very useful. And I finally found a way to solve my problem. Hooray~~~

Note:
	- the usage of include
	- use markdownify to tranform page.content to markdown format
	- the difference between relative and definite directory
	- the usage of viewport