Update README.md

Author: skywinder

README.md

@@ -124,32 +124,61 @@ $ pod install
 - [x] Manage user's private keys through encrypted keystore abstractions
 - [x] Batched requests in concurrent mode, checks balances of 580 tokens (from the latest MyEtherWallet repo) over 3 seconds
 
-## Usage
+## Getting started
 
-Here's a few use cases of our library:
+Here's a few use cases:
 
 ### Create Account
-Create keystore and account with password.
 
-```
+```swift
+    // Create keystore and account with password.
+    
 	let keystore = try! EthereumKeystoreV3(password: "changeme"); // generates a private key internally if node "privateKey" parameter supplied
         let account = keystore!.addresses![0]
         print(account)
+	
         let data = try! keystore!.serialize() // internally serializes to JSON
         print(try! JSONSerialization.jsonObject(with: data!, options: JSONSerialization.ReadingOptions(rawValue:0)))
-        let key = try! keystore!.UNSAFE_getPrivateKeyData(password: "changeme", account: account) // you should rarely use this and expose a key manually
+        let key = try! keystore!.UNSAFE_getPrivateKeyData(password: "changeme", account: account) // you should rarely use this and expose a key manually	
 ```
 
-### Initializing Ethereum address
+### Save keystore to the memory
+
+```swift
+//First you need a `KeystoreManager` instance:
+guard let userDirectory = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first,
+    let keystoreManager = KeystoreManager.managerForPath(userDirectory + "/keystore")
+else {
+    fatalError("Couldn't create a KeystoreManager.")
+}
+
+//Next you create the a new Keystore:
+
+let newKeystore = try? EthereumKeystoreV3(password: "YOUR_PASSWORD")
+
+// Then you save the created keystore to the file system:
+
+let newKeystoreJSON = try? JSONEncoder().encode(newKeystore.keystoreParams)
+FileManager.default.createFile(atPath: "\(keystoreManager.path)/keystore.json", contents: newKeystoreJSON, attributes: nil)
+
+// Later you can retreive it:
+
+if let address = keystoreManager.addresses?.first,
+let retrievedKeystore = keystoreManager.walletForAddress(address) as? EthereumKeystoreV3 {
+    return retrievedKeystore
+}
 ```
+
+### Initializing Ethereum address
+```swift
 let coldWalletAddress = EthereumAddress("0x6394b37Cf80A7358b38068f0CA4760ad49983a1B")
 let constractAddress = EthereumAddress("0x45245bc59219eeaaf6cd3f382e078a461ff9de7b", ignoreChecksum: true)
 ```
 Ethereum addresses are checksum checked if they are not lowercased or uppercased and always length checked
 
 ### Setting options
 
-```
+```swift
 var options = Web3Options.defaultOptions()
     // public var to: EthereumAddress? = nil - to what address transaction is aimed
     // public var from: EthereumAddress? = nil - form what address it should be sent (either signed locally or on the node)
@@ -173,21 +202,21 @@ options.from = EthereumAddress("0xE6877A4d8806e9A9F12eB2e8561EA6c1db19978d")
 //TODO
 ```
 ### Getting ETH balance
-```
+```swift
 let address = EthereumAddress("0xE6877A4d8806e9A9F12eB2e8561EA6c1db19978d")!
 let web3Main = Web3.InfuraMainnetWeb3()
 let balanceResult = web3Main.eth.getBalance(address)
 guard case .success(let balance) = balanceResult else {return}
 ```
 ### Getting gas price
-```
+```swift
 let web3Main = Web3.InfuraMainnetWeb3()
 let gasPriceResult = web3Main.eth.getGasPrice()
 guard case .success(let gasPrice) = gasPriceResult else {return}
 ```
 
 ### Sending ETH
-```
+```swift
 let web3Rinkeby = Web3.InfuraRinkebyWeb3()
 web3Rinkeby.addKeystoreManager(bip32keystoreManager) // attach a keystore if you want to sign locally. Otherwise unsigned request will be sent to remote node
 options.from = bip32ks?.addresses?.first! // specify from what address you want to send it
@@ -198,7 +227,7 @@ let sendResultBip32 = intermediateSend.send(password: "changeme")
 ### ERC20 Iteraction:
 
 #### Getting ERC20 token balance
-```
+```swift
 let contractAddress = EthereumAddress("0x45245bc59219eeaaf6cd3f382e078a461ff9de7b")! // BKX token on Ethereum mainnet
 let contract = web3.contract(Web3.Utils.erc20ABI, at: contractAddress, abiVersion: 2)! // utilize precompiled ERC20 ABI for your concenience
 guard let bkxBalanceResult = contract.method("balanceOf", parameters: [coldWalletAddress] as [AnyObject], options: options)?.call(options: nil) else {return} // encode parameters for transaction
@@ -207,7 +236,7 @@ print("BKX token balance = " + String(bal))
 ```
 
 #### Sending ERC20
-```
+```swift
 var convenienceTransferOptions = Web3Options.defaultOptions()
 convenienceTransferOptions.gasPrice = gasPriceRinkeby
 let convenienceTokenTransfer = web3Rinkeby.eth.sendERC20tokensWithNaturalUnits(tokenAddress: EthereumAddress("0xa407dd0cbc9f9d20cdbd557686625e586c85b20a")!, from: (ks?.addresses?.first!)!, to: EthereumAddress("0x6394b37Cf80A7358b38068f0CA4760ad49983a1B")!, amount: "0.0001", options: convenienceTransferOptions) // there are also convenience functions to send ETH and ERC20 under the .eth structure