Generalize docker-entrypoint for further flask commands

docker-entrypoint.sh

 #!/bin/sh
 
-if [[ $# -eq 0 ]]
+if [ $# -eq 0 ]
 then
-  venv/bin/python -u opaque.py
-elif [[ $1 == "--migrate" ]]
-  then
-    echo Migrating changes.
-    venv/bin/python -m flask db migrate
-    venv/bin/python -m flask db upgrade
+    venv/bin/python -u opaque.py
+elif [ $1 == "flask" ]
+then
+    echo "$@"
+    venv/bin/python -m $@
 else
-  if [[ $1 == "--setup-database" ]]
-  then
-    echo Initial setup of database.
-    venv/bin/python -m flask db init
-    venv/bin/python -m flask db upgrade
-    venv/bin/python -m flask insert-initial-database-entries
-  fi
+    echo "Unknown command"
 fi