Upload files to "docs"

docs/configuration.md

@@ -0,0 +1,63 @@
+# Configuration Guide
+
+GemReader uses a TOML-based configuration file to customize the application behavior. The configuration file is named `config.toml` and should be placed in the same directory where you run the application.
+
+## Default Configuration File
+
+The default `config.toml` file looks like this:
+
+```toml
+title = "GemReader"
+```
+
+## Available Configuration Options
+
+### title
+
+- **Type**: String
+- **Default**: "GemReader"
+- **Description**: Sets the title displayed at the top of the application interface
+
+### default_file
+
+- **Type**: String
+- **Default**: "" (empty)
+- **Description**: Sets the default markdown file to open when no file is provided as a command-line argument
+
+## Configuration Loading
+
+The application attempts to load the configuration file when it starts. If the file is not found or contains errors, the application will continue to run with default settings.
+
+The configuration is loaded using the [Viper](https://github.com/spf13/viper) library, which supports:
+
+1. Loading from `config.toml` in the current directory
+2. Environment variable overrides (with `GEMREADER_` prefix)
+3. Default fallback values
+
+## Example Advanced Configuration
+
+While the current version only supports the title configuration, future versions may support additional options:
+
+```toml
+title = "My Markdown Viewer"
+
+# These options are planned for future releases:
+# theme = "dark"          # Color theme (dark/light)
+# toc_enabled = true      # Whether to generate table of contents
+# line_numbers = false    # Show line numbers
+# wrap_text = true        # Wrap long lines
+```
+
+## Troubleshooting
+
+### Configuration File Not Found
+
+If the application starts but the custom title isn't displayed, ensure that:
+
+1. The `config.toml` file exists in the current working directory
+2. The file has the correct format and valid TOML syntax
+3. The application has read permissions for the file
+
+### Invalid Configuration
+
+If the configuration file contains invalid TOML syntax, the application will log an error and use default values instead.