This project is created to backup feeds and documents on friendfeed.
But the intention is to do more than that.

updater.php
-----------
Download the latest entries in JSON format using ff API. Inserts entries and
all of their sub-properties into FFDB. Stops when the number of changed entries
gets below a certain threshold.

Sources of feeds are kept in source relation (table) of FFDB.

file_downloader.php
-------------------
Downloads the files from the files relation of FFDB. After downloading,
determines the type of the file and inserts the info into BooksDb. Keeps track
of what is already downloaded and what is not.

FFDB.php
--------
Provides a basic data model for the database operations on FFDB. FFDB stores
the FF related data, such as entries, comments, feed sources etc.

BookDb.php
----------
Provides a basic data model for the database operation on BookDb. BookDb stores
the data over actual books, such as author, title, language, filename etc.

credentials.php
---------------
Required credentials to connect to FF API, namely username and remote_key (
https://friendfeed.com/remotekey ).

config.php
----------
Condiguration options, e.g., download directories, db filenames.

ffdb.dat
bookdb.dat
----------
Sqlite databases for ff entries and books.

db_*_schema.sql
---------------
SQL schema file for the specified DB.

db_*_intial.sql
---------------
Initial sql queries that should be run on the specified DB before first use.