Add success story add/edit and list (#4)

still a work in progress

src/JobsJobsJobs/Server/Data/SuccessExtensions.cs

@@ -0,0 +1,34 @@
+using JobsJobsJobs.Shared;
+using JobsJobsJobs.Shared.Api;
+using Microsoft.EntityFrameworkCore;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace JobsJobsJobs.Server.Data
+{
+    /// <summary>
+    /// Extensions to JobsDbContext to support manipulation of success stories
+    /// </summary>
+    public static class SuccessExtensions
+    {
+        /// <summary>
+        /// Get a success story by its ID
+        /// </summary>
+        /// <param name="id">The ID of the story to retrieve</param>
+        /// <returns>The success story, if found</returns>
+        public static async Task<Success?> FindSuccessById(this JobsDbContext db, SuccessId id) =>
+            await db.Successes.AsNoTracking().SingleOrDefaultAsync(s => s.Id == id).ConfigureAwait(false);
+
+        /// <summary>
+        /// Get a list of success stories, with the information needed for the list page
+        /// </summary>
+        /// <returns>A list of success stories, citizen names, and dates</returns>
+        public static async Task<IEnumerable<StoryEntry>> AllStories(this JobsDbContext db) =>
+            await db.Successes
+                .Join(db.Citizens, s => s.CitizenId, c => c.Id, (s, c) => new { Success = s, Citizen = c })
+                .OrderByDescending(it => it.Success.RecordedOn)
+                .Select(it => new StoryEntry(it.Success.Id, it.Citizen.Id, it.Citizen.DisplayName, it.Success.RecordedOn))
+                .ToListAsync().ConfigureAwait(false);
+    }
+}