Fixed duplicated key issue

Closes #18

I18N Commander/Processor/SectionProcessor.cs

@@ -34,6 +34,17 @@ public static class SectionProcessor
     {
         // Remove any whitespaces from the section name, regardless of how many e.g. spaces the user typed:
         var key = string.Join('_', text.Split(' ', StringSplitOptions.TrimEntries | StringSplitOptions.RemoveEmptyEntries)).ToUpperInvariant();
+        
+        // Check, if this key already exists:
+        if (await db.Sections.AnyAsync(n => n.DataKey == key))
+        {
+            var rng = new Random();
+            while (await db.Sections.AnyAsync(n => n.DataKey == key))
+            {
+                // Add a random number to the end of the key:
+                key += $"_{rng.Next(1, 10_000)}";
+            }
+        }
 
         // In the case, when the user adds a section to the root, handle the insert differently:
         if (string.IsNullOrEmpty(parentKey))