feat(backend): add basic sensor endpoints

backend/src/main/java/org/mercury/backend/BackendApplication.java

@@ -3,11 +3,16 @@ package org.mercury.backend;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RestController;
 
 @SpringBootApplication
 @RestController
 public class BackendApplication {
+
+	private SensorData sensorData;
+
 	public static void main(String[] args) {
 		SpringApplication.run(BackendApplication.class, args);
 	}
@@ -16,4 +21,15 @@ public class BackendApplication {
 	public String hello() {
 		return String.format("Server up and running!");
 	}
+
+	@PostMapping("/sensor")
+	SensorData newEmployee(@RequestBody SensorData sensorData) {
+		this.sensorData = sensorData;
+		return sensorData;
+	}
+
+	@GetMapping("/sensor")
+	SensorData getSensorData() {
+		return sensorData;
+	}
 }

backend/src/main/java/org/mercury/backend/SensorData.java

@@ -0,0 +1,4 @@
+package org.mercury.backend;
+
+public record SensorData(double temperature, double humidity) {
+}