package de.metalmatze.krautreporter.helpers;

import android.app.Application;

public class KrautreporterApplication extends Application {

    private static KrautreporterApplication instance;

    public static KrautreporterApplication get() {
        return instance;
    }

    @Override
    public void onCreate() {
        super.onCreate();

        instance = this;
    }
}

package de.metalmatze.krautreporter.helpers;

import android.app.Application;

import io.realm.Realm;
import io.realm.RealmConfiguration;

public class KrautreporterApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();

        RealmConfiguration configuration = new RealmConfiguration.Builder(this)
                .deleteRealmIfMigrationNeeded()
                .build();

        Realm.getInstance(configuration);
    }
}

Add RealmConfiguration to KrautreporterApplication