feat: Add an example to show how to load GenerationOptions from a json string

examples/options_from_json.rs

@@ -0,0 +1,30 @@
+use ollama_rs::{
+    generation::{completion::request::GenerationRequest, options::GenerationOptions},
+    Ollama,
+};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let ollama = Ollama::default();
+    let model = "llama2:latest".to_string();
+    let prompt = "Why is the sky blue?".to_string();
+
+    // Fetch the configuration from a file or from user request
+    // let options_str = fs::read_to_string("options.json").expect("The option file should be available")    ;
+    let options_str = r#"{
+      "temperature": 0.2,
+      "repeat_penalty": 1.5,
+      "top_k": 25,
+      "top_p": 0.25
+    }"#;
+    let options: GenerationOptions =
+        serde_json::from_str(options_str).expect("JSON was not well-formatted");
+    let res = ollama
+        .generate(GenerationRequest::new(model, prompt).options(options))
+        .await;
+
+    if let Ok(res) = res {
+        println!("{}", res.response);
+    }
+    Ok(())
+}