Update preprocessor.py

preprocessor.py

 import json
+from jsonschema import validate
 
 with open('recipes/vegancupcakes.json', 'r') as f:
     recipes = json.load(f)
@@ -31,5 +32,7 @@ def addMissingUnits():
     pass
 
 # Check that everything in the database conforms to the schema
-def conform():
-    pass
+def validateSchema():
+    # for each json file in database/
\ No newline at end of file
+    validate(schema, file)
+    
\ No newline at end of file