Show error dialog on migration failure

src-tauri/yaak-models/src/error.rs

@@ -20,6 +20,9 @@ pub enum Error {
 
     #[error("Model error: {0}")]
     GenericError(String),
+    
+    #[error("DB Migration Failed: {0}")]
+    MigrationError(String),
 
     #[error("No base environment for {0}")]
     MissingBaseEnvironment(String),