Feature add product 6

Issue #5 
Issue #6 
Issue #9 
Issue #10 
Issue #11 

### Review ###
- [x] Added 3 more attributes; tag, color & category
- [x] Renamed `content` to `description`
- [x] Hide unnecessary links; like help pages


### Test ###
- [x] run testcases by executing this cmd: `grunt test` or `grunt mochaTest`
- [x] Test manually
 * Add product; only title & description are mandatory fields
 * Update product
 * Delete product
 * Listing will show only title & description
 * Detail page contain all attributes information