Enum support for csharp-dotnet2

Description

The language csharp-dotnet2 does not generate valid enum definitions. Enum support was implemented for csharp, but still doesn't exist for csharp-dotnet2.

Swagger-codegen version

2.4.0

Swagger declaration file content or url

        "Portion": {
            "enum": [
                "T",
                "F",
                "R",
                "M"
            ],
            "type": "string"
        }

And the resulting type is

using System;
using System.Text;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.Serialization;
using Newtonsoft.Json;

namespace IO.Swagger.Model {

  /// <summary>
  /// 
  /// </summary>
  [DataContract]
  public class Portion {

    /// <summary>
    /// Get the string presentation of the object
    /// </summary>
    /// <returns>String presentation of the object</returns>
    public override string ToString()  {
      var sb = new StringBuilder();
      sb.Append("class Portion {\n");
      sb.Append("}\n");
      return sb.ToString();
    }

    /// <summary>
    /// Get the JSON string presentation of the object
    /// </summary>
    /// <returns>JSON string presentation of the object</returns>
    public string ToJson() {
      return JsonConvert.SerializeObject(this, Formatting.Indented);
    }

}
}

Command line used for generation

java -jar swagger-codegen-cli.jar generate -i swagger.json -o gen -l csharp-dotnet2

Related issues/PRs

#2429

Suggest a fix/enhancement

Could probably re-use same mustache template (e.g. modelEnum) as for csharp

Start by comparing enum support for csharp with the csharp-dotnet2 generator and the modelEnum Mustache template mentioned in the issue. Run the provided swagger-codegen command with the sample declaration; done means csharp-dotnet2 generates Portion as a valid C# enum rather than an empty class.