docs: add comprehensive README documentation (#163)

- Add environment variables documentation with descriptions and defaults
- Document complete application workflow from startup to transaction submission
- Include building and running instructions
- Provide clear overview of the Cardano indexer and reward system

Signed-off-by: Chris Gianelloni <[email protected]>

Author: wolf31o2

README.md

@@ -1 +1,79 @@
-# buidler-fest-2024-workshop
+# buidler-fest-2024-workshop
+
+A Cardano blockchain indexer and reward system that monitors transactions and automatically sends rewards based on configurable criteria.
+
+## Environment Variables
+
+The application uses environment variables to configure its behavior. You can set these variables in your environment or create a `.env` file in the project root.
+
+### General
+- `NETWORK`: Cardano network to use (default: `preprod`)
+
+### Indexer
+Use one of the following:
+- `INDEXER_TCP_ADDRESS`: TCP address and port of the remote Cardano Node for the indexer
+- `INDEXER_SOCKET_PATH`: Socket path of the local Cardano Node for the indexer
+
+### Reward
+- `MIN_LOVELACE`: Minimum Lovelace required to trigger a reward (default: `50_000_000`)
+- `REWARD_ADDRESS`: Address to send rewards to
+- `REWARD_AMOUNT`: Amount of Lovelace to send as a reward (default: `5_000_000`)
+- `SOURCE_ADDRESS`: Source address to filter transactions
+
+### Submit
+Use one of the following:
+- `SUBMIT_TCP_ADDRESS`: TCP address and port of the remote Cardano Node for transaction submission
+- `SUBMIT_SOCKET_PATH`: Socket path of the local Cardano Node for transaction submission
+- `SUBMIT_URL`: API URL for transaction submission
+
+### TxBuilder
+Use one of the following:
+- `BLOCKFROST_API_KEY`: Blockfrost API key for UTxO queries
+- `KUPO_URL`: Kupo URL for UTxO queries
+
+### Wallet
+- `MNEMONIC`: Wallet mnemonic (if not set, will use or generate `seed.txt`)
+
+## Application Workflow
+
+### 1. Startup (`cmd/workshop/main.go`)
+- The main entry point is the `main()` function
+- Loads configuration from environment variables and `.env` file
+- Sets up logging
+- Initializes the wallet (loads or generates mnemonic)
+- Starts the indexer
+
+### 2. Wallet Setup (`internal/wallet/wallet.go`)
+- Loads mnemonic from config or `seed.txt`
+- If not present, generates a new mnemonic and writes it to `seed.txt`
+- Initializes the wallet for use
+
+### 3. Indexer (`internal/indexer/indexer.go`)
+- Creates a pipeline to listen for transaction events on the configured network and addresses
+- Filters events for relevant addresses (wallet and reward)
+- On transaction events, triggers the transaction builder
+
+### 4. Transaction Builder (`internal/txbuilder/txbuilder.go`)
+- Handles transaction events
+- Checks if the transaction meets reward criteria (source address, minimum Lovelace, etc.)
+- Builds a reward transaction if criteria are met
+- Signs the transaction with the wallet keys
+
+### 5. Transaction Submission (`internal/txsubmit/txsubmit.go`)
+- Submits the built transaction to the network via TCP, socket, or API, depending on config
+
+## Building and Running
+
+To build the application:
+
+```bash
+make build
+```
+
+To run the application:
+
+```bash
+./workshop
+```
+
+The application will run continuously, monitoring the blockchain for transactions and automatically sending rewards when criteria are met.