Updates Register guide to use programmatic CLI. (#256)

Author: johnnymatthews

content/guides/register-an-account.md

@@ -8,29 +8,60 @@ lead: "Registering an account is a feature unique to Entropy. Without going into
 Here is the process for registering an address using the Entropy CLI's interactive text-based user interface (TUI).
 
 1. Start the CLI by running `entropy tui`.
-1. Back at the main menu within the CLI, select **Register**:
+1. Select **Register**:
 
-   ```output
-   ? Select Action
+    ```output
+    ? Select Action (Use arrow keys)
      Manage Accounts
+     Entropy Faucet
      Balance
-   > Register
+    ❯ Register
      Sign
      Transfer
      Deploy Program
      User Programs
      Exit
-   ```
+    ```
 
-1. The CLI will send your selected account information to the network. As long as you have enough funds in your account, the network will register your account.
+1. The CLI will send your selected account information to the network. As long as you have enough funds, the network will register your account.
 
-   ```output
-   Attempting to register the address: 5Dcps2RdXPQfiJBxxDnrF8iDzDHcnZC8rb5mcJ3xicqzhYbv
-   Your address 5Dcps2RdXPQfiJBxxDnrF8iDzDHcnZC8rb5mcJ3xicqzhYbv has been successfully registered.
-   ```
+    ```output
+    Attempting to register the address: 5EFDfxft4oZYvjj35TWttFkkKZSHUDVnBRmp3eMQQcpt9zku
+    Your address 5EFDfxft4oZYvjj35TWttFkkKZSHUDVnBRmp3eMQQcpt9zku has been successfully registered.
+    ```
 
 1. Press `Y` to go back to the main menu.
 
-## SDK
+You can check that your account is registered by navigating to **Manage Accounts** and selecting **List Accounts**. Accounts that have been registered will have `verifyingKeys`:
 
-The feature is not currently available in the SDK.
+```output
+{
+  "name": "Andre",
+  "address": "5F3xmKa3WRkoHR4o6XjFQaWF2EskhtSh4ST5wY5cfsD9JYbC",
+  "verifyingKeys": []
+}
+{
+  "name": "Yoel",
+  "address": "5EFDfxft4oZYvjj35TWttFkkKZSHUDVnBRmp3eMQQcpt9zku",
+  "verifyingKeys": [
+    "0x03aee03ad9862e9f31d06f7d1b4b388ad1c66152ad17f919fc16fcc75929b08db3",
+    "0x029d00ff44b70613228963e45a05fe743ea92beb8ece19d48fb6c60d66386fe03b"
+  ]
+}
+```
+
+In the above example, the `Yoel` key has been registered, while the `Andre` key has not.
+
+## Programmatic CLI
+
+You can use the `account register` commands to register an account. You must have created an account _before_ attempting to register it. The account must also have enough funds to request registration from the network. After a successful registration, the CLI will output the verifying key of the account:
+
+```shell
+entropy account register --account 'Yoel'
+```
+
+```output
+0x029d00ff44b70613228963e45a05fe743ea92beb8ece19d48fb6c60d66386fe03b
+```
+
+See the [Command-line interface reference]({{<relref "command-line-interface">}}) section for more details on the `account register` commands.