Database for Folder

Added tables:

• folders(id, user_id, name, is_root, created_on),
• file_folder(id_file, id_parent), and
• folder_folder(id_folder, id_parent).

Folder feature:

• A folder can contain folders and files
• There's a special folder called root folder, recognized by the TRUE value on the is_root attribute in the folders table
• Each user is assigned a root folder upon account creation (perlu tambahin di sign up). A root folder has been assigned for each existing user in the SQL query
• All folders (except root folder) is a child of a folder. Likewise, every files is a child of a folder. This relation is implemented in the file_folder and folder_folder tables

Effect on existing features:

• Account sign up creates an entry for the root folder in the folders table
• Home page (or similar pages that previously display all user files) now by default displays folders & files in a particular folder, not all the files owned by a user, unless we need that for some use cases. These pages should now use GetFilesByFolderId instead of GetFiles
• Menyambung poin di atas, the Home page (or similar pages) displays folders & files in the root folder by default. The user can then navigate through folders as usual