Enhance Dockerfile and Streamlit app for secret management and environment variable usage

- Added support for secret management in Dockerfile to expose the mongo_uri at build time and set it as the git remote URL.
- Updated Streamlit app to retrieve the MongoDB URI from environment variables instead of directly from secrets, improving flexibility in deployment.

Dockerfile

@@ -14,6 +14,11 @@ COPY src/ ./src/
 
 RUN pip3 install -r requirements.txt
 
+# Expose the secret SECRET_EXAMPLE at buildtime and use its value as git remote URL
+RUN --mount=type=secret,id=mongo_uri,mode=0444,required=true \
+    git init && \
+    git remote add origin $(cat /run/secrets/mongo_uri)
+
 EXPOSE 8501
 
 HEALTHCHECK CMD curl --fail http://localhost:8501/_stcore/health

src/streamlit_app.py

@@ -2,12 +2,13 @@ import streamlit as st
 import numpy as np
 import pandas as pd
 import pymongo
+import os
 
 st.set_page_config(layout="wide")
 
 @st.cache_resource
 def init_conn():
-        uri = st.secrets['mongo_uri']
+        uri = os.getenv('mongo_uri')
         client = pymongo.MongoClient(uri, retryWrites=True, serverSelectionTimeoutMS=500000)
         db = client["MLB_Database"]