Save words into selected folder in the user's database

[kacieyee]

Use Firebase to store each user's data. The highlighted words can go into a default folder like "All highlighted words", but users should be able to select a specific folder (or create a new one) to save words into.

Ex folders: All highlighted words, Engineering-related, News-related etc

Users will have multiple languages as well, so for example, user could have three folders for "Japanese" and five folders for "German".