Add markdown guide to link a device (#20)

* Add markdown guide to link a device
* Add guide to ex_doc

Board_Registration.md

@@ -0,0 +1,74 @@
+
+# Register Your GRiSP2 Board with GRiSP.io
+
+Welcome! This guide walks you through linking your GRiSP2 board to your GRiSP.io account. Begin with obtaining a unique linking token, then choose between automatic or manual registration based on your preference.
+
+## Obtain Your Device Linking Token
+
+To start, you'll need a unique token:
+
+1. **Log In or Sign Up:** Navigate to [GRiSP.io](https://grisp.io) and access your account or create a new one.
+2. **Get Your Token:** Visit the [GRiSP Manager](https://grisp.io/grisp-manager/) to request a new Linking Token by clicking on **Link Device**. This token is crucial for the next steps in both automatic and manual registration methods.
+
+---
+
+With your token ready, select one of the following options to register your GRiSP2 board:
+
+## Option 1: Automatic Linking with grisp_auto_link
+
+For a hassle-free experience:
+
+- **Download the Binary Package:** Look for the [grisp_auto_link](https://github.com/grisp/grisp_auto_link) zip file on the GRiSP Manager page under the **Link Device** section. It comes pre-configured with your linking token.
+- **Prepare Your SD Card:** Extract the zip file onto a Fat32 formatted SD card and insert it into your GRiSP2 board.
+- **Initiate Automatic Registration:** Connect your board to the internet via an ethernet cable. It will automatically link to your GRiSP.io account, which you can verify on the GRiSP Manager.
+
+## Option 2: Manual Linking (For Advanced Users)
+
+If you prefer a hands-on approach or need custom setup:
+
+1. **Project Setup:** Follow the [GRiSP Wiki](https://github.com/grisp/grisp/wiki) for instructions on creating and deploying your GRiSP2 application. Before proceeding, ensure `grisp_io` is added to your project's dependencies. This is a crucial step for manual linking.
+
+   - **Optional Configuration:** To streamline the process, include the device_linking_token in your project's release configuration (`config/sys.config`):
+    ```erlang
+    [
+        {grisp_io, [
+            {device_linking_token, <<"your_token_here">>}
+        ]}
+    ].
+    ```
+
+    This allows you to skip manually entering the token in the future.
+
+2. **Deploy Your Application:** After setting up, make sure your board is connected to the internet. You can verify that your board connected to GRiSP.io executing:
+   ```erlang
+   > grisp_io:is_connected().
+   true
+   ```
+
+3. **Manually Link Your Board:** Access the Erlang shell on your board. To link, execute:
+   ```erlang
+   > grisp_io:link_device(<<"your_unique_token">>).
+   ```
+   Or, if your token is pre-configured in the environment, run:
+   ```erlang
+   > grisp_io:link_device().
+   ```
+
+4. **Check Registration Status:** A successfull request returns `{ok, <<"ok">>}`. Confirm your device's registration on the [GRiSP Manager](https://grisp.io/grisp-manager/) page. Your device should appear under the **Devices** section. :tada:
+
+### Troubleshooting:
+`grisp_io:link_device/*` may fail with the following errors.
+#### **Common Errors:**
+- `token_expired`: regenerate one from the web page
+- `invalid_token`: please double check you typed it correctly
+- `token_undefined`: you called `grisp_io:link_device/0` without setting `device_linking_token`
+- `disconnected`: check that your board can connect
+- `device_already_linked`: please do not steal GRiSP boards :smirk:
+  if you need to unlink a GRiSP board see below...
+
+
+## Need to Unlink a Device?
+
+We currently do not expose a public API to unlink a Device. Please reach out to us for assistance.
+
+If you encounter any problems or have questions, don't hesitate to contact [support](mailto:[email protected]). Happy coding!

README.md

@@ -2,6 +2,10 @@
 
 GRiSP.io Client Library for GRiSP
 
+Add this application as a dependency in your GRiSP2 project.
+Your board will connect securely through Mutual TLS to the [GRiSP.io](https://grisp.io) services.
+See this [LINKING](https://github.com/grisp/grisp_io/blob/main/LINKING.md) guide on how to start using your GRiSP2 board with GRiSP.io
+
 ## Application env options
 
 ### connect

rebar.config

@@ -35,6 +35,7 @@
     {extras, [
           {"CHANGELOG.md", #{title => "Changelog"}},
           {"README.md", #{title => "Overview"}},
+          {"Board_Registration.md", #{title => "Board Registration"}},
           {"LICENSE", #{title => "License"}}
     ]},
     {main, "README.md"},