Added category-alias related changes

[vibharaj]

Hello Matt,

I am working on Issue #5: Users should have some way to edit keyword aliases.
I have done the following:

1. I created a service called databaseCategoryAliasesService and added the CRUD operations for category-aliases.
   This service operates on a separate json file called category-aliases-db.
2. I updated the routes.js and json-routes files as well
3. I created a component called CategoryAliasesDatabaseComponent and that helps edit the category-aliases
4. Now, there is an additional table of category and aliases in the Database tab and there is a place to add category and aliases in the Add Snippets tab.
5. I also modified the current parse description service to integrate aliases.

Per my last email, I finished the following:

• Create a separate JSON file for the category-alias mapping.
• Create a new component to do CRUD operations for the category-alias mapping
• Provide a way to go and edit aliases from the database view
• Modify the current parser to look up aliases when it considers keywords

Please review and let me know your thoughts on what I have completed.

Thanks!