fix: fixing the issue on the initialization of the web application

Adding .env.example for environment variable management
Updating .gitignore to exclude sensitive files
Modifying pom.xml to include new dependencies
Updating application.properties for better configuration

pom.xml

@@ -48,6 +48,16 @@
       <artifactId>spring-boot-starter-test</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>com.h2database</groupId>
+      <artifactId>h2</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.springframework.security</groupId>
+      <artifactId>spring-security-test</artifactId>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
   <build>
     <plugins>