Fix NLTK data path and other adjustments

app.py

@@ -11,10 +11,12 @@ from nltk.corpus import stopwords
 from fpdf import FPDF
 from collections import Counter
 
-# Download risorse NLTK
-nltk.download("punkt")
-nltk.download("wordnet")
-nltk.download("stopwords")
+# Download risorse NLTK (incluso punkt)
+nltk.download('punkt', download_dir='/home/user/nltk_data')
+nltk.download('wordnet', download_dir='/home/user/nltk_data')
+nltk.download('stopwords', download_dir='/home/user/nltk_data')
+
+nltk.data.path.append("/home/user/nltk_data")
 
 lemmatizer = WordNetLemmatizer()
 stemmer = PorterStemmer()