Add blockchain directory for working on related projects

+ Add sample Solidity project template, README instructions

blockchain/eth/truffle-solidity/.gitignore

@@ -0,0 +1,5 @@
+secrets.json
+build/
+cache/
+node_modules/
+.idea/

blockchain/eth/truffle-solidity/README.md

@@ -0,0 +1,84 @@
+
+A template project for getting started working on the Ethereum blockchain.
+This project comes with basic packages for compiling and deploying Solidity contracts with Truffle.
+
+Run `cp example.secrets.json secrets.json` and fill out the copied `secrets.json` with your information.
+
+From this directory, run `npm install` to install required packages.
+
+From there, we can create any contracts and deploy to development or public networks...
+### Development Deploy
+
+```asm
+npx truffle develop
+truffle(develop)> migrate
+
+Compiling your contracts...
+===========================
+> Compiling ./contracts/Migrations.sol
+> Artifacts written to /home/kapper/Code/klips/blockchain/eth/truffle-solidity/build/contracts
+> Compiled successfully using:
+   - solc: 0.8.0+commit.c7dfd78e.Emscripten.clang
+
+
+
+Starting migrations...
+======================
+> Network name:    'develop'
+> Network id:      5777
+> Block gas limit: 6721975 (0x6691b7)
+
+
+1_initial_migration.js
+======================
+
+   Deploying 'Migrations'
+   ----------------------
+   > transaction hash:    0xa82aeb7e6e3839f06321edc4b41fdb92e70f87b9a989f846fd465623deda4139
+   > Blocks: 0            Seconds: 0
+   > contract address:    0xD79FAf957cC8d3d6c7f8fc10875D8aF75e4eE9F1
+   > block number:        1
+   > block timestamp:     1620058221
+   > account:             0xcFE4341F1DFEbdff039642e1A26032755F38ADA5
+   > balance:             99.995114
+   > gas used:            244300 (0x3ba4c)
+   > gas price:           20 gwei
+   > value sent:          0 ETH
+   > total cost:          0.004886 ETH
+
+
+   > Saving migration to chain.
+   > Saving artifacts
+   -------------------------------------
+   > Total cost:            0.004886 ETH
+
+
+Summary
+=======
+> Total deployments:   1
+> Final cost:          0.004886 ETH
+
+
+- Blocks: 0            Seconds: 0
+- Saving migration to chain.
+
+truffle(develop)> .exit
+```
+
+### Public Network Deploy
+
+To deploy, you need ETH on a wallet connected to ropsten. Metamask is the wallet I use.
+I explain how to configure metamask on ropsten on [Knoats - Solidity](https://knoats.com/books/c/page/solidity)
+
+Give yourself test Ethereum with the [Ropsten ETH Faucet](https://faucet.ropsten.be)
+
+To deploy to ropsten test network, and verify using `truffle-verify-plugin` - 
+
+```asm
+npx truffle migrate --network ropsten
+npx truffle run verify Migrations --network ropsten
+```
+
+For a guide on how I configured this project, see [Knoats - Solidity](https://knoats.com/books/c/page/solidity)
+
+An example ERC20 token can be found at [shaunrd0/karma](https://gitlab.com/shaunrd0/karma)

blockchain/eth/truffle-solidity/contracts/Migrations.sol

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.4.22 <0.9.0;
+
+contract Migrations {
+  address public owner = msg.sender;
+  uint public last_completed_migration;
+
+  modifier restricted() {
+    require(
+      msg.sender == owner,
+      "This function is restricted to the contract's owner"
+    );
+    _;
+  }
+
+  function setCompleted(uint completed) public restricted {
+    last_completed_migration = completed;
+  }
+}

blockchain/eth/truffle-solidity/example.secrets.json

@@ -0,0 +1,5 @@
+{
+  "alchemyApiUrl": "https://eth-ropsten.alchemyapi.io/v2/YOUR_ALCHEMY_API_KEY",
+  "mnemonic": "word word word word word word word word word word word",
+  "etherscanApiKey": "SOMEREALLYLONGKEYFROMETHERSCAN"
+}

blockchain/eth/truffle-solidity/migrations/1_initial_migration.js

@@ -0,0 +1,5 @@
+const Migrations = artifacts.require("Migrations");
+
+module.exports = function (deployer) {
+  deployer.deploy(Migrations);
+};

blockchain/eth/truffle-solidity/package.json

@@ -0,0 +1,17 @@
+{
+  "name": "upgradeable-ERC20",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "Shaun Reed",
+  "license": "ISC",
+  "devDependencies": {
+    "@openzeppelin/contracts": "^4.1.0",
+    "@truffle/hdwallet-provider": "^1.3.0",
+    "truffle": "^5.3.4"
+  }
+}

blockchain/eth/truffle-solidity/truffle-config.js

@@ -0,0 +1,120 @@
+/**
+ * Use this file to configure your truffle project. It's seeded with some
+ * common settings for different networks and features like migrations,
+ * compilation and testing. Uncomment the ones you need or modify
+ * them to suit your project as necessary.
+ *
+ * More information about configuration can be found at:
+ *
+ * trufflesuite.com/docs/advanced/configuration
+ *
+ * To deploy via Infura you'll need a wallet provider (like @truffle/hdwallet-provider)
+ * to sign your transactions before they're sent to a remote public node. Infura accounts
+ * are available for free at: infura.io/register.
+ *
+ * You'll also need a mnemonic - the twelve word phrase the wallet uses to generate
+ * public/private key pairs. If you're publishing your code to GitHub make sure you load this
+ * phrase from a file you've .gitignored so it doesn't accidentally become public.
+ *
+ */
+
+const HDWalletProvider = require('@truffle/hdwallet-provider');
+const { alchemyApiUrl, mnemonic, etherscanApiKey } = require('./secrets.json');
+// const infuraKey = "fj4jll3k.....";
+//
+// const fs = require('fs');
+// const mnemonic = fs.readFileSync(".secret").toString().trim();
+
+module.exports = {
+  plugins: [
+    'truffle-plugin-verify'
+  ],
+  api_keys: {
+    etherscan: etherscanApiKey
+  },
+  /**
+   * Networks define how you connect to your ethereum client and let you set the
+   * defaults web3 uses to send transactions. If you don't specify one truffle
+   * will spin up a development blockchain for you on port 9545 when you
+   * run `develop` or `test`. You can ask a truffle command to use a specific
+   * network from the command line, e.g
+   *
+   * $ truffle test --network <network-name>
+   */
+
+  networks: {
+    // Useful for testing. The `development` name is special - truffle uses it by default
+    // if it's defined here and no other network is specified at the command line.
+    // You should run a client (like ganache-cli, geth or parity) in a separate terminal
+    // tab if you use this network and you must also set the `host`, `port` and `network_id`
+    // options below to some value.
+    //
+    // development: {
+    //  host: "127.0.0.1",     // Localhost (default: none)
+    //  port: 8545,            // Standard Ethereum port (default: none)
+    //  network_id: "*",       // Any network (default: none)
+    // },
+    // Another network with more advanced options...
+    // advanced: {
+    // port: 8777,             // Custom port
+    // network_id: 1342,       // Custom network
+    // gas: 8500000,           // Gas sent with each transaction (default: ~6700000)
+    // gasPrice: 20000000000,  // 20 gwei (in wei) (default: 100 gwei)
+    // from: <address>,        // Account to send txs from (default: accounts[0])
+    // websocket: true        // Enable EventEmitter interface for web3 (default: false)
+    // },
+    // Useful for deploying to a public network.
+    // NB: It's important to wrap the provider as a function.
+    ropsten: {
+      provider: () => new HDWalletProvider({
+        mnemonic: {
+          phrase: mnemonic
+        },
+        providerOrUrl: alchemyApiUrl,
+        chainId: 3
+      }),
+      // provider: () => new HDWalletProvider('turtle erupt shop aisle north segment clarify soda excuse help love snake', `https://eth-ropsten.alchemyapi.io/v2/msUAyuwMjIDj72x461sgdmXLxPcVm4eP`),
+      network_id: 3,       // Ropsten's id
+      gas: 5500000,        // Ropsten has a lower block limit than mainnet
+      confirmations: 2,    // # of confs to wait between deployments. (default: 0)
+      timeoutBlocks: 200,  // # of blocks before a deployment times out  (minimum/default: 50)
+      skipDryRun: true     // Skip dry run before migrations? (default: false for public nets )
+    },
+    // Useful for private networks
+    // private: {
+    // provider: () => new HDWalletProvider(mnemonic, `https://network.io`),
+    // network_id: 2111,   // This network is yours, in the cloud.
+    // production: true    // Treats this network as if it was a public net. (default: false)
+    // }
+  },
+
+  // Set default mocha options here, use special reporters etc.
+  mocha: {
+    // timeout: 100000
+  },
+
+  // Configure your compilers
+  compilers: {
+    solc: {
+      version: "0.8.0",    // Fetch exact version from solc-bin (default: truffle's version)
+      // docker: true,        // Use "0.5.1" you've installed locally with docker (default: false)
+      // settings: {          // See the solidity docs for advice about optimization and evmVersion
+      //  optimizer: {
+      //    enabled: false,
+      //    runs: 200
+      //  },
+      //  evmVersion: "byzantium"
+      // }
+    }
+  },
+
+  // Truffle DB is currently disabled by default; to enable it, change enabled: false to enabled: true
+  //
+  // Note: if you migrated your contracts prior to enabling this field in your Truffle project and want
+  // those previously migrated contracts available in the .db directory, you will need to run the following:
+  // $ truffle migrate --reset --compile-all
+
+  db: {
+    enabled: false
+  }
+};