Add authentication

Website/Data/UserRepository.cs

@@ -0,0 +1,25 @@
+using System.Linq;
+using System.Threading.Tasks;
+using Dapper;
+using Website.Data.States;
+using Website.Models;
+
+namespace Website.Data {
+	public class UserRepository {
+		private readonly IDatabaseProvider _dbProvider;
+
+		public UserRepository(IDatabaseProvider dbProvider) {
+			_dbProvider = dbProvider;
+		}
+
+		public async Task<User> GetUserByEmail(string email) {
+			const string query = "SELECT * FROM users WHERE user_email=@email";
+
+			using (var connection = _dbProvider.NewConnection()) {
+				connection.Open();
+				var result = await connection.QueryAsync<UserState>(query, new {email});
+				return new User(result.Single());
+			}
+		}
+	}
+}