Android + AndroidAnnotations REST API

I am trying to create a simple learning project with AndroidAnnotations, which will work with REST calls. I have followed this tutorial
https://github.com/androidannotations/androidannotations/wiki/Rest-API#rest

but with no luck. Project builds successfully, but at runtime, my @RestService is always null and I cannot get it to work.

Here is how my structure looks like:

build.gradle
apply plugin: 'com.android.application'

def AAVersion = '4.3.0'
dependencies {
    annotationProcessor "org.androidannotations:androidannotations:$AAVersion"
    compile "org.androidannotations:androidannotations-api:$AAVersion"
    compile "org.androidannotations:rest-spring-api:$AAVersion"
    compile 'com.fasterxml.jackson.core:jackson-core:2.7.2'
    compile 'org.springframework.android:spring-android-rest-template:2.0.0.M3'
}

Interface (separate file):

@Rest(rootUrl = "https://api.github.com", converters = {StringHttpMessageConverter.class})
public interface GithubClient {

    @Get("/search/repositories?q={searchString}")
    GitResult getResult(@Path String searchString);

}

MainActivity:

public class MainActivity extends AppCompatActivity {

    @RestService
    GithubClient restClient;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Click(R.id.btn_Request)
    void requestCall(){
        searchAsync();
    }

    @Background
    void searchAsync(){
        try {
            GitResult result = restClient.getResult("angular");
        } catch (RestClientException e){
            Log.e("Rest error",e.toString());
        }

    }
}

AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.com.githubbrowser">
    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity_">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Am I missing any package, or what am I doing wrong here? Any help or recommendations would be highly appreciated.

So the problem was that I was missing the following dependencies under build.gradle:

compile "org.androidannotations:rest-spring:$AAVersion"
compile 'com.fasterxml.jackson.core:jackson-databind:2.3.2'