feat: Update Spring Boot version and add OpenAPI documentation

pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>3.5.6</version>
+        <version>3.2.0</version>
         <relativePath/> <!-- lookup parent from repository -->
     </parent>
     <groupId>com.muchemi</groupId>
@@ -67,6 +67,11 @@
             <artifactId>h2</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.springdoc</groupId>
+            <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
+            <version>2.5.0</version>
+        </dependency>
     </dependencies>
 
     <build>

src/main/java/com/muchemi/expense_tracker/ExpenseTrackerApplication.java

@@ -1,10 +1,19 @@
 package com.muchemi.expense_tracker;
 
+import io.swagger.v3.oas.annotations.OpenAPIDefinition;
+import io.swagger.v3.oas.annotations.info.Info;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
 
+@OpenAPIDefinition(
+        info = @Info(
+                title = "Expense Tracker API",
+                version = "1.0",
+                description = "API for managing personal expenses"
+        )
+)
 @SpringBootApplication
 @RestController
 public class ExpenseTrackerApplication {

src/main/java/com/muchemi/expense_tracker/controllers/CategoryController.java

@@ -19,7 +19,7 @@ public class CategoryController {
     public CategoryController(CategoryService categoryService) {
         this.categoryService = categoryService;
     }
-
+    
     @PostMapping
     public ResponseEntity<CategoryResponseDTO> createCategory(@Valid @RequestBody CategoryRequestDTO request) {
         CategoryResponseDTO response = categoryService.createNewCategory(request);