Add 'Signing and releasing' page

Work done soley by @alessandrojean

Co-Authored-By: Alessandro Jean <14254807+alessandrojean@users.noreply.github.com>

website/src/.vitepress/config/navigation/sidebar.ts

@@ -112,6 +112,10 @@ function defaultSidebar(): DefaultTheme.SidebarItem[] {
               text: 'Compiling and running',
               link: '/docs/guides/creating-extensions/compiling',
             },
+            {
+              text: 'Signing and releasing',
+              link: '/docs/guides/creating-extensions/signing',
+            },
           ],
         },
         {

website/src/docs/guides/creating-extensions/signing.md

@@ -0,0 +1,97 @@
+---
+title: Signing and releasing
+titleTemplate: Creating extensions - Guides
+description: Signing and releasing the repository
+---
+
+# Signing and releasing
+
+To setup the GitHub actions to automatically release new extensions on every push, you will need to setup a signing key.
+To do that, you need to create one first.
+
+## Creating a signing key
+
+The following steps will guide you into creating a key.
+
+1. On Android Studio, open **Build → Generate Signed Bundle or APK**. Under the new screen, choose the **APK** option and click **Next**.
+2. Click on **Create new…** under the **Key store path** field.
+3. Fill up the required fields in the **New Key Store** window.
+
+    The fields under the Certificate section are optional, but you will need to fill at least one of them.
+4. Click **OK** and it will create the signing key at the path choosen at the **Key store path** field.
+5. You can close the **Generate Signed Bundle or APK** window as it will not be used anymore.
+
+::: tip
+Make sure to remember the given values of **Password**, **Alias** and **Key Password** as they will be needed later.
+:::
+
+::: danger Caution
+Make sure to not use any special characters such as `@` or `!` under any of the passwords, otherwise it will lead to the generation of broken keys.
+:::
+
+## Configuring the GitHub actions
+
+This section will guide you into setting up the secrets needed for the build and also some options you need to change under the repository settings.
+
+### Adding the secrets
+
+All secrets depends on a generated signed key which was described in the previous section.
+
+1. In your repository on GitHub, open the **Settings** tab and navigate to **Secrets and variables → Actions**.
+2. Under the **Secrets** tab, you will need to create four secrets by following the table below.
+
+    - `ALIAS`: The value of the key alias;
+    - `KEY_PASSWORD`: The main password of the key;
+    - `KEY_STORE_PASSWORD`: The password of the key store;
+    - `SIGNING_KEY`: Base-64 representation of the key `.jks` file content;
+
+#### Creating the Base-64 representation
+
+Under a terminal window in the path of the key, you can use the following command to convert the key and copy the value.
+
+```bash
+$ base64 signingkey.jks | tr -d \\n | xclip -selection c
+```
+
+The previous command depends on `xclip` installed to copy the contents of the conversion to the clipboard, but you can replace that last part with any other similar tool.
+
+:::warning Caution
+Make sure your copied value doesn't have any trailing whitespace while pasting the value under GitHub.
+:::
+
+### Enabling Actions read and write permission
+
+The workflows will need write permissions to commit to the `repo` branch.
+
+1. Under the repository Settings on GitHub, navigate to **Actions → General**.
+2. Choose the **Read and write permissions** option on the **Workflow permissions** section and click **Save**.
+
+### Creating an empty `repo` branch
+
+If your repository doesn't already have a `repo` branch, you will need to create it.
+
+To create you can follow the standard flow of creating a `branch` named `repo` and then proceed by deleting all repository files (except the `.git`) folder and then commiting and pushing to GitHub.
+
+### Changing the checks in the workflow
+
+If your repository is forked or cloned from the official extensions repository, you will need to change two checks under the `.github/workflows/build_push.yml` file.
+
+```yml
+- name: Upload APKs
+  uses: actions/upload-artifact@v4
+  if: "github.repository == 'tachiyomiorg/extensions'" # [!code --]
+  if: "github.repository == '[user]/[repository]'" # [!code ++]
+```
+
+```yml
+publish_repo:
+  name: Publish repo
+  needs:
+    - build_individual
+  if: "github.repository == 'tachiyomiorg/extensions'" # [!code --]
+  if: "github.repository == '[user]/[repository]'" # [!code ++]
+```
+
+### Finishing up
+
+If all is configured correctly, GitHub should run the workflow whenever there's a new commit pushed to the `main` branch which will build the extensions APKs and release it through the `repo` branch by creating the needed structure.