Add Vitepress docs (#326)

* Add vitepress for docs

* some fix

* Use vitepress and update docs

* Use vitepress and update docs

* Update README.md

* Add favicon

* Add docs by @jiriks74

Co-authored-by: jiriks74 <jiri@stefka.eu>

---------

Co-authored-by: jiriks74 <jiri@stefka.eu>

docs/configuration/admin-panel.md

@@ -0,0 +1,53 @@
+# Admin panel
+
+The first user created on your Opengist instance has access to the Admin panel.
+
+To access the Admin panel:
+
+1. Log in
+2. Click your username in the upper right corner
+3. Select `Admin`
+
+## Usage
+
+### General
+
+Here you can see some basic information, like Opengist version, alongside some stats.
+
+You can also start some actions like forcing synchronization of gists,
+starting garbage collection, etc.
+
+### Users
+
+Here you can see your users and delete them.
+
+### Gists
+
+Here you can see all the gists and some basic information about them. You also have an option
+to delete them.
+
+
+### Invitations
+
+Here you can create invitation links with some options like limiting the number of signed up
+users or setting an expiration date.
+
+> [!Note]
+> Invitation links override the `Disable signup` option but not the `Disable login form` option.
+>
+> Users will see only the OAuth providers when `Disable login form` is enabled.
+
+### Configuration
+
+Here you can change a limited number of settings without restarting the instance.
+
+- Disable signup
+    - Forbid the creation of new accounts.
+- Require login
+    - Enforce users to be logged in to see gists.
+- Allow individual gists without login
+    - Allow individual gists to be viewed and downloaded without login, while requiring login for discovering gists.
+- Disable login form
+    - Forbid logging in via the login form to force using OAuth providers instead.
+- Disable Gravatar
+    - Disable the usage of Gravatar as an avatar provider.

docs/configuration/cheat-sheet.md

@@ -1,3 +1,7 @@
+---
+aside: false
+---
+
 # Configuration Cheat Sheet
 
 | YAML Config Key       | Environment Variable                | Default value         | Description                                                                                                                                                                                                                      |

docs/configuration/configure.md

@@ -27,7 +27,7 @@ Usage via command line :
 ./opengist --config /path/to/config.yml
 ```
 
-You can start by copying and/or modifying the provided [config.yml](/config.yml) file.
+You can start by copying and/or modifying the provided [config.yml](https://github.com/thomiceli/opengist/blob/stable/config.yml) file.
 
 
 ## Configuration via Environment Variables

docs/configuration/custom-links.md

@@ -52,11 +52,11 @@ If you want your custom page to integrate well into the existing theme, you can
    </header>
    <main>
      <h3 class="text-xl font-bold leading-tight mt-4">Sub-Heading</h3>
-     <p class="mt-4 ml-1"><!-- content --></p>
+     <p class="mt-4 ml-1"><!-- my content --></p>
    </main>
 </div>
 
 {{ template "footer" . }}
 ```
 
-You can adjust above as needed. Opengist uses Tailwind CSS classes.
+You can adjust above as needed. Opengist uses TailwindCSS classes.

docs/configuration/oauth-providers.md

@@ -0,0 +1,77 @@
+# Use OAuth providers
+
+Opengist can be configured to use OAuth to authenticate users, with GitHub, Gitea, or OpenID Connect.
+
+## GitHub
+
+* Add a new OAuth app in your [GitHub account settings](https://github.com/settings/applications/new)
+* Set 'Authorization callback URL' to `http://opengist.url/oauth/github/callback`
+* Copy the 'Client ID' and 'Client Secret' and add them to the [configuration](cheat-sheet.md) :
+  ```yaml
+  github.client-key: <key>
+  github.secret: <secret>
+  ```
+  ```shell
+  OG_GITHUB_CLIENT_KEY=<key>
+  OG_GITHUB_SECRET=<secret>
+  ```
+
+
+## GitLab
+
+* Add a new OAuth app in Application settings from the [GitLab instance](https://gitlab.com/-/user_settings/applications)
+* Set 'Redirect URI' to `http://opengist.url/oauth/gitlab/callback`
+* Copy the 'Client ID' and 'Client Secret' and add them to the [configuration](cheat-sheet.md) :
+  ```yaml
+  gitlab.client-key: <key>
+  gitlab.secret: <secret>
+  # URL of the GitLab instance. Default: https://gitlab.com/
+  gitlab.url: https://gitlab.com/
+  ```
+  ```shell
+  OG_GITLAB_CLIENT_KEY=<key>
+  OG_GITLAB_SECRET=<secret>
+  # URL of the GitLab instance. Default: https://gitlab.com/
+  OG_GITLAB_URL=https://gitlab.com/
+  ```
+  
+
+
+## Gitea
+
+* Add a new OAuth app in Application settings from the [Gitea instance](https://gitea.com/user/settings/applications)
+* Set 'Redirect URI' to `http://opengist.url/oauth/gitea/callback`
+* Copy the 'Client ID' and 'Client Secret' and add them to the [configuration](cheat-sheet.md) :
+  ```yaml
+  gitea.client-key: <key>
+  gitea.secret: <secret>
+  # URL of the Gitea instance. Default: https://gitea.com/
+  gitea.url: http://localhost:3000
+  ```
+  ```shell
+  OG_GITEA_CLIENT_KEY=<key>
+  OG_GITEA_SECRET=<secret>
+  # URL of the Gitea instance. Default: https://gitea.com/
+  OG_GITEA_URL=http://localhost:3000
+  ```
+  
+
+
+## OpenID Connect
+
+* Add a new OAuth app in Application settings of your OIDC provider
+* Set 'Redirect URI' to `http://opengist.url/oauth/openid-connect/callback`
+* Copy the 'Client ID', 'Client Secret', and the discovery endpoint, and add them to the [configuration](cheat-sheet.md) :
+  ```yaml
+  oidc.client-key: <key>
+  oidc.secret: <secret>
+  # Discovery endpoint of the OpenID provider. Generally something like http://auth.example.com/.well-known/openid-configuration
+  oidc.discovery-url: http://auth.example.com/.well-known/openid-configuration
+  ```
+  ```shell
+  OG_OIDC_CLIENT_KEY=<key>
+  OG_OIDC_SECRET=<secret>
+  # Discovery endpoint of the OpenID provider. Generally something like http://auth.example.com/.well-known/openid-configuration
+  OG_OIDC_DISCOVERY_URL=http://auth.example.com/.well-known/openid-configuration
+  ```
+