Create directory if it does not exist

Fixes #12

src/ServerManagerDiscordBot/ServerManager.cs

@@ -123,7 +123,7 @@ public async Task<IEnumerable<FileInfo>> GetServerFilesAsync(string name, Cancel
         var directory = new DirectoryInfo(server.FilesPath);
         if (!directory.Exists)
         {
-            throw new DirectoryNotFoundException($"The `{name}` server files directory `{server.FilesPath}` does not exist.");
+            directory.Create();
         }
 
         var files = directory.EnumerateFiles();
@@ -161,7 +161,7 @@ public async Task<IEnumerable<FileInfo>> GetServerGalleryFilesAsync(string name,
         var directory = new DirectoryInfo(server.GalleryPath);
         if (!directory.Exists)
         {
-            throw new DirectoryNotFoundException($"The `{name}` server gallery directory `{server.GalleryPath}` does not exist.");
+            directory.Create();
         }
 
         var files = directory.EnumerateFiles()
@@ -179,6 +179,12 @@ public async Task UploadServerGalleryFileAsync(string name, string sourceUrl, st
             throw new InvalidOperationException($"The `{name}` server does not support this operation.");
         }
 
+        var directory = new DirectoryInfo(server.GalleryPath);
+        if (!directory.Exists)
+        {
+            directory.Create();
+        }
+
         if (!AppSettings.GalleryFileExtensions.Contains(Path.GetExtension(fileName).Substring(1), StringComparer.OrdinalIgnoreCase))
         {
             throw new ArgumentException($"The gallery does not support the file type `{Path.GetExtension(fileName)}`.");