Added user stuff to Dockerfile to handle permission issues

Dockerfile

@@ -1,10 +1,14 @@
 FROM ohif/app:v3.7.0-beta.74
 
+# first set user as root to add new user (then later change to user)
+USER root
+
 # Set up a new user named "user" with user ID 1000
-#RUN useradd -m -u 1000 user
+# RUN useradd -m -u 1000 user
+RUN adduser -D -u 1000 "user"
 
 # Switch to the "user" user
-#USER user
+USER user
 
 # Set home to the user's home directory
 ENV HOME=/home/user \