Provide a way of reading from the Secrets config file

[rustd]

Project Templates will create a file to store secrets for the app
File will be created in the following folder
 Windows - AppData/Roaming/Microsoft/AspNetUserSecrets/UserSecretsId/config.secrets.json
Project.json will have the following: "userSecretsId": "aspnet5-WebApplication108-GUID",The value is the same logic we use to specify database name in config.json
Template code to read config will be as follows

public Startup(IHostingEnvironment env, IApplicationEnvironment app)
        {
            // Setup configuration sources.
            Configuration = new Configuration()
                .AddJsonFile("config.json");

            if (env.EnvironmentName =="Development" )
            {
                 Configuration.AddUserSecrets();
            }
            else
            {
                Configuration.AddJsonFile("config." + env.EnvironmentName + ".json", true)
            }
             Configuration.AddEnvironmentVariables();
        }

[muratg]

Hey @Praburaj can you have a look? These are tooling blocking issues.

/cc @rustd @DamianEdwards

[Praburaj]

This bug will depend on #123.

[Praburaj]

Merged : 7a4af7d

[Praburaj]

Usage :

To install the user-secret tool globally:

dnu commands install SecretManager

Now open any command prompt and navigate to the project path (location of the project.json). To add a secret for the project (and do not forget to add a "userSecretsId" : "Your secretsId" value to your project.json):
user-secret set Facebook:AppId secretValue

To consume the secrets from your web application include the secrets configuration in to your app by calling the AddUserSecrets extension on your configuration object.