How can I bring this BaseRepository inside my controller and get it's method

I am using an ORM to connect to the database it is called dapper. The issue with it is that it's database calls are synchronous and I recently found a way to make it asynchronous by following this short tutorial http://www.joesauve.com/async-dapper-and-async-sql-connection-management/ . My question is how can I bring this BaseRepository into my Controller class ? This is the code on that website and it's the same one I have

BaseRepository- by the way there is no issue in this code

 public abstract class BaseRepository 
   {

private readonly string _ConnectionString;

protected BaseRepository(string connectionString) 
{
    _ConnectionString = connectionString;
}

protected async Task<T> WithConnection<T>(Func<IDbConnection, Task<T>> getData) 
{
    try {
        using (var connection = new SqlConnection(_ConnectionString)) {
            await connection.OpenAsync(); // Asynchronously open a connection to the database
            return await getData(connection); // Asynchronously execute getData, which has been passed in as a Func<IDBConnection, Task<T>>
        }
    }
    catch (TimeoutException ex) {
        throw new Exception(String.Format("{0}.WithConnection() experienced a SQL timeout", GetType().FullName), ex);
    }
    catch (SqlException ex) {
        throw new Exception(String.Format("{0}.WithConnection() experienced a SQL exception (not a timeout)", GetType().FullName), ex);
    }
}
}

and now he brings it in like this

public class PersonRepository : BaseRepository
{
    public PersonRepository(string connectionString): base (connectionString) { }

    public async Task<Person> GetPersonById(Guid Id)
    {
        return await WithConnection(async c => {

            // Here's all the same data access code,
            // albeit now it's async, and nicely wrapped
            // in this handy WithConnection() call.
            var p = new DynamicParameters();
            p.Add("Id", Id, DbType.Guid);
            var people = await c.QueryAsync<Person>(
                sql: "sp_Person_GetById", 
                param: p, 
                commandType: CommandType.StoredProcedure);
            return people.FirstOrDefault();

        });
    }
}

The part I am having a problem with is this public class PersonRepository : BaseRepositorybecause Asp.Net Controllers start with public class HomeController: Controller , I need access to the WithConnection method to get this working. My controller looks like this

public class HomeController : Controller
    {

        public class ConnectionRepository : BaseRepository
        {
            public ConnectionRepository(string connectionString) : base(connectionString) { }

        }
      public async Task<ActionResult> topfive()
            {
    // I get Error on WithConnection as it can't see the BaseRepository
                return await WithConnection(async c =>
                {


                    var topfive = await c.QueryAsync<Streams>("select * from streams ").ToList();
                return View(topfive);
                });

 }
            }

I obviously can not cover my ActionResult method with the BaseRepository because it gives all types of errors any suggestions ?