fix typo

examples/geo_alchemy/README.rst

@@ -14,7 +14,7 @@ To run this example:
 
 3. Install requirements::
 
-    pip install -r 'examples/geo-alchemy/requirements.txt'
+    pip install -r 'examples/geo_alchemy/requirements.txt'
 
 4. Setup the database::
 
@@ -36,4 +36,4 @@ To run this example:
 
 6. You will notice that the maps are not rendered. To see them, you will have
 to register for a free account at `Mapbox <https://www.mapbox.com/>`_ and set
-the *MAPBOX_MAP_ID* and *MAPBOX_ACCESS_TOKEN* config variables accordingly.
\ No newline at end of file
+the *MAPBOX_MAP_ID* and *MAPBOX_ACCESS_TOKEN* config variables accordingly.