Add colours to tags
Fix only count one visit before refreshing
If you visit root A and then root B, and then C, only the visit of root A will increase.
Create a help page
A few improvements for new root page
1. Jump to the newly-created root page after creating
2. Add an instruction about how to add tags
Display tags on the root page
Display tags better on 'tags' page
Get ready for comments and mainlines