Refactor ledger processing to explicit mapping which will make automated classfication easy

README.md

@@ -1,6 +1,9 @@
-# defaultpy
+# ledgerai
 
-Default Python project.
+Script to transform CSV data into [ledger](https://ledger-cli.org/) accounting
+files.
+
+# Usage
 
 Run `pipenv install -dev` to install all packages.
 
@@ -8,3 +11,20 @@ Run `pipenv shell` to get venv shell.
 
 Run `pipenv install <package>` to install a package.
 
+# Architecture
+
+The script takes a directory in which it recursively searches for CSV and LDG
+files. From these files, it generates a single ledger accounting file that
+includes all transactions.
+
+For now, ledger files are simply appended to the output file without
+modifications.
+
+However, the transaction for the CSV files are extended with their *account2*
+information, i.e, the category of the transaction. Optionally, these
+transactions can also get a more meaningful description and tags.
+
+The mapping information are stored in a file `mappings.json`. It maps a unique
+identifier for each transaction (based on filename, line number) to the
+respective *account2*, and (optinally) *tags* or *description.
+