Changes to Courses Endpoints

[devppratik]

Following changes are required to back-end

• Add a CP category on the create-article route
• Rename topic to tag
• Article must contain multiple tags

The following endpoints need to be created/ modified

• create-article - Tags should be passed as an array of items. Each article must be linked to that tag
• tag-detail/<slug> - GET all articles under the tag
• tag-list - GET all tags. Also add new tag wiith POST request
• category-detail - GET all tracks under a category