Rough version of Saving Series, Volumes, and MangaFiles to the DB. Relies on Cascaded delete rather than manually handling updating of file changes.

API/Data/SeriesRepository.cs

@@ -0,0 +1,43 @@
+using System.Linq;
+using System.Threading.Tasks;
+using API.Entities;
+using API.Interfaces;
+using Microsoft.EntityFrameworkCore;
+
+namespace API.Data
+{
+    public class SeriesRepository : ISeriesRepository
+    {
+        private readonly DataContext _context;
+
+        public SeriesRepository(DataContext context)
+        {
+            _context = context;
+        }
+
+        public void Update(Series series)
+        {
+            _context.Entry(series).State = EntityState.Modified;
+        }
+
+        public async Task<bool> SaveAllAsync()
+        {
+            return await _context.SaveChangesAsync() > 0;
+        }
+        
+        public bool SaveAll()
+        {
+            return _context.SaveChanges() > 0;
+        }
+
+        public async Task<Series> GetSeriesByNameAsync(string name)
+        {
+            return await _context.Series.SingleOrDefaultAsync(x => x.Name == name);
+        }
+        
+        public Series GetSeriesByName(string name)
+        {
+            return _context.Series.SingleOrDefault(x => x.Name == name);
+        }
+    }
+}