docs: add configuration based config for repository context (#2299)

website/docs/administration/context/index.mdx

@@ -12,7 +12,7 @@ import CodeBrowserUrl from "./code-browser.png";
 
 The repository context is used to connect Tabby with a source code repository from Git, GitHub, GitLab, etc. Tabby fetches the source code from the repository, parses it into an AST, and stores it in the index. During LLM inference, this context is utilized for code completion, as well as chat and search functionalities.
 
-## Adding a Repository Provider
+## Adding a Repository through Admin UI
 
 1. Navigate to the **Integrations > Repository Providers** page.
 
@@ -33,6 +33,26 @@ The repository context is used to connect Tabby with a source code repository fr
 
     <img src={SelectRepoUrl} alt="select-repo" width="700" />
 
+## Adding a Repository through configuration file
+
+`~/.tabby/config.toml` is the configuration file for Tabby. You can add repositories with it as well, and it's also the only way to add a repository for the Tabby OSS.
+
+```toml title="~/.tabby/config.toml"
+[[repositories]]
+name = "tabby"
+git_url = "https://github.com/TabbyML/tabby.git"
+
+# git through ssh protocol.
+[[repositories]]
+name = "CTranslate2"
+git_url = "[email protected]:OpenNMT/CTranslate2.git"
+
+# local directory is also supported!
+[[repositories]]
+name = "repository_a"
+git_url = "file:///home/users/repository_a"
+```
+
 ## Verifying the Repository Provider
 
 Once connected, the indexing job will start automatically. You can check the status of the indexing job on the **Information > Jobs** page.