docs: exercise for c2d2 (#20)

* Init c2d2 instructions

* Update

* Update

* docs(c2d2): add container run instructions

* update

* Add instruction for pull image

* Update

* docs(c2d2): complete exercise 2

* docs(c2d2): fix

Co-authored-by: jack <[email protected]>

Exercises/exercise_2_btc_transfer_with_c2d2.md

@@ -0,0 +1,129 @@
+# Exercise 2
+Transfer BTC to Ethereum (as a wrapped asset) and back using `c2d2cli`.
+
+C2D2 is the axelar cross-chain dapp deamon which coordinates the necessary transactions for cross-chain asset transfers.
+The C2D2 CLI automates the steps we performed manually in exercise 1.
+
+## Disclaimer 
+Axelar Network is a work in progress. At no point in time should you transfer any real assets using Axelar. Only use testnet tokens that you're not afraid to lose. Axelar is not responsible for any assets lost, frozen, or unrecoverable in any state or condition. If you find a problem, please submit an issue to this repository following the template. 
+
+## Prerequisites
+- Complete all steps from `README.md`
+
+## What you need
+- Bitcoin testnet wallet with some tBTC (faucet [https://testnet-faucet.mempool.co/](https://testnet-faucet.mempool.co/))
+- Ethereum wallet on the Ropsten network (we reccomend Metamask)
+- Some Ropsten ETH (faucet [https://faucet.ropsten.be/](https://faucet.ropsten.be/))
+
+## Joining the Axelar testnet
+
+Follow the instructions in `README.md` to make sure your node is synchronized to the latest block, and you have received some test coins to your validator account. 
+
+### Pull C2D2 docker image
+Check [TESTNET RELEASE.md](../TESTNET%20RELEASE.md) for the latest available C2D2 version of the docker images.
+
+```
+docker pull axelarnet/c2d2:VERSION
+```
+
+### Enter the `c2d2cli` container
+On a new terminal window, enter the `c2d2cli` container by running:
+```
+./c2d2/c2d2cli.sh
+```
+
+### Generate a key on Axelar and get some test tokens
+
+Create c2d2's Axelar blockchain account
+```
+c2d2cli keys add c2d2
+```
+
+Go to axelar faucet and fund your C2D2 account by providing the address to the
+facuet (http://faucet.testnet.axelar.network/).\ You can get c2d2's account
+address by running 
+
+```
+c2d2cli keys show C2D2 -a
+```
+
+### Mint ERC20 Bitcoin tokens on Ethereum
+1. Generate a Bitcoin deposit address. The Ethereum address you provide will be linked to the deposit address and receive the pegged bitcoin (Satoshi tokens) on the Ethereum testnet. 
+
+    ```
+    `c2d2cli` deposit-btc ethereum [ethereum recipient address]
+    ```
+
+    You will see the deposit Bitcoin address printed in the terminal
+
+    ```
+    > Please deposit Bitcoin to bcrt1qk4s6ya3gqakzmpv95tvgp00rhpkal9jyx243y8dr2dzmttkcdurq4dqj4t
+    > Waiting for deposit transaction
+    ```
+
+2. *External*: send some TEST BTC on Bitcoin testnet to the deposit address specific above, and wait for 6 confirmations (i.e. the transaction is 6 blocks deep in the Bitcoin chain). 
+
+  - ALERT: **DO NOT SEND ANY REAL ASSETS**
+  - Bitcoin testnet faucet [https://testnet-faucet.mempool.co/](https://testnet-faucet.mempool.co/)
+  - You can monitor the status of your deposit using the testnet explorer: [https://blockstream.info/testnet/](https://blockstream.info/testnet/)
+
+Do not exit `c2d2cli` while you are waiting for your deposit to be confirmed. It will be watching for an event from the bitcoin bridge node which it needs to detect your transaction.
+
+If your bitcoin deposit transaction has at least 1 confirmation but is not
+detected, you can restart `c2d2cli` and append the `--bitcoin-tx-prompt` flag.
+The CLI will prompt you to enter the deposit tx info manually. The rest of the
+deposit procedure will still be automated.
+
+    ```
+    `c2d2cli` deposit-btc ethereum [ethereum recipient address] --bitcoin-tx-prompt
+    ```
+
+Once your transaction is detected, `c2d2cli` will wait until it has 6 confirmations before proceeding.
+
+ 3. C2D2 will automate the bitcoin deposit confirmation, and mint command signing and sending. Once the minting process completes you will see the following message:
+
+    ```
+    Mint command <commandId> completed at ethereum txID <transactionId>
+    ```
+
+You can now open Metamask and add the wrapped BTC contract address. `c2d2cli` will print the contract address like this:
+
+```
+Using satoshi token <address>
+```
+
+The contract will show in metamask as symbol 'Satoshi'. If your recipient address is in metamask, you will have an amount of satoshi tokens in metamask equal to your bitcoin deposit. 
+
+### Burn ERC20 wrapped Bitcoin tokens and obtain native Satoshi
+1. Generate an ethereum withdrawal address. The Bitcoin address you provide will be uniquely linked to the deposit address and receive the withdrawn BTC on the Bitcoin testnet. 
+
+   ```
+   `c2d2cli` withdraw-btc ethereum [bitcoin recipient address] [fee]
+   ```
+
+For example:
+   ```
+   `c2d2cli` withdraw-btc ethereum tb1qg2z5jatp22zg7wyhpthhgwvn0un05mdwmqgjln 10000satoshi
+   ```
+
+You will see the deposit Ethereum address printed in the terminal.
+
+   ```
+   > Please transfer satoshi tokens to 0xC21f7876a23E2E7EB7e4A92E1AF03cacf14B59d5
+   > Waiting for withdrawal transaction...
+   ```
+
+2. External: send wrapped Satoshi tokens to withdrawal address (e.g. with Metamask). You need to have some Ropsten testnet Ether on the address to send transactions.
+
+
+3. Once your withdrawal transaction is detected, `c2d2cli` will wait for 30 Ropsten block confirmations before proceeding.
+
+
+4. C2D2 will automate the withdrawal confirmation, and bitcoin transaction signing and sending. It will then complete the bitcoin change outpoint confirmation and satoshi token burning.
+
+
+5. Once your bitcoin is withdrawn and your Satoshi tokens have been burned, you will see this message:
+
+```
+Burn command <command id> completed at ethereum txID <tx hash>
+```

TESTNET RELEASE.md

@@ -4,5 +4,6 @@ Variable  | Value
 ------------- | -------------
 `axelar-core` version | `v0.3.1`
 `tofnd` version | `v0.2.0`
+`c2d2` version | `v0.1.0`
 Ethereum address for sending transactions | `0xE3deF8C6b7E357bf38eC701Ce631f78F2532987A`
 Ethereum token contract address | `0x728C6f7865996178A8852530b7998EA77cb6364c`