feat: added nano install for ease of use

DOCKERFILE

@@ -15,7 +15,7 @@ WORKDIR /downdetector
 # Update and install dependencies
 RUN apt update && \
     apt upgrade -y && \
-    apt install -y bash curl vim cron
+    apt install -y bash curl vim nano cron
 
 # Copy files
 COPY isalive.sh .