create a new user after creating a fresh db

Makefile

@@ -89,4 +89,4 @@ show-data-model:
 	./flexmeasures/data/scripts/visualize_data_model.py --uml
 
 clean-db:
-	./flexmeasures/data/scripts/clean_database.sh ${db_name}
+	./flexmeasures/data/scripts/clean_database.sh ${db_name} ${db_user}

documentation/tut/toy-example-from-scratch.rst

@@ -103,11 +103,11 @@ Install Flexmeasures and the database
 
         .. note:: When installing with ``pip``, on some platforms problems might come up (e.g. macOS, Windows). One reason is that FlexMeasures requires some libraries with lots of C code support (e.g. Numpy). One way out is to use Docker, which uses a prepared Linux image, so it'll definitely work.
 
-        In case you want to re-run the tutorial, then it's recommended to delete the old database and create a fresh one. Run the following command to create a clean database.
+        In case you want to re-run the tutorial, then it's recommended to delete the old database and create a fresh one. Run the following command to create a clean database with a new user, where it is optional. If you don't provide the user, then the default `postgres` user will be used to create the database.
 
         .. code-block:: bash
 
-            $ make clean-db db_name=flexmeasures-db
+            $ make clean-db db_name=flexmeasures-db [db_user=flexmeasures]
 
 Add some structural data
 ---------------------------------------

flexmeasures/data/scripts/clean_database.sh

@@ -4,15 +4,64 @@ MAIN_DIR=$(pwd)
 
 # function for checking database existence
 function is_database() {
- cd /tmp
- sudo -u postgres psql -lqt | cut -d \| -f 1 | grep -wq $1
- cd ${MAIN_DIR}
+  sudo -i -u postgres psql -lqt | cut -d \| -f 1 | grep -wq $1
+}
+
+# check if the user exists
+function is_user() {
+  if sudo -i -u postgres psql -tAc "SELECT 1 FROM  pg_roles WHERE rolname='$1'" | grep -q 1; then
+    echo "$1 is already available."
+    return 0 # success (user exists)
+  else
+    echo "$1 is not created before."
+    return 1 # failure (user does not exist)
+  fi
+}
+
+# create a new user
+function create_user() {
+   echo "Creating database user ..."
+   read -s -p "Enter password for new user: " password
+   echo ""
+   read -s -p "Confirm password for new user: " password_confirm
+   echo ""
+
+   if [ "$password" != "$password_confirm" ]; then
+      echo "Error: Passwords do not match. Exiting..."
+      exit 1
+   fi
+   sudo -i -u postgres psql -c "CREATE USER $1 WITH PASSWORD '$password'"
+}
+
+# function to give the required privileges to the newly created user
+function grant_privileges(){
+  echo "Connect $2 to $1 "
+   sudo -i -u postgres psql -c "GRANT CONNECT ON DATABASE $1 TO $2"
+   echo "Grant required privileges"
+   sudo -i -u postgres psql -c "GRANT USAGE, SELECT, INSERT, UPDATE, DELETE ON ALL TABLES IN SCHEMA public TO $2"
 }
 
 # function for creating a new database
 function create_database() {
  echo "Creating a new database ..."
  sudo -i -u postgres createdb -U postgres $1
+
+ if [[ -n "$2" ]];
+    then
+      # check if the user exists
+      if is_user $2
+        then
+          # give the required permissions to the user
+          grant_privileges $1 $2
+      else
+        # if user doesn't exist, first create it and then give the permissions.
+        if create_user $2
+          then
+            grant_privileges $1 $2
+        fi
+      fi
+ fi
+
  echo "Creating cube extension in $1 ..."
  sudo -i -u postgres psql -c "\c $1" -c "CREATE EXTENSION cube;"
  echo "Creating earthdistance extension in $1 ..."
@@ -29,7 +78,7 @@ function delete_database() {
 
 # Check if the database name is provided
 if [ -z "$1" ]; then
-  echo "Error: db_name is required. Please provide a value for db_name, e.g., make clean_db db_name=flexmeasures-db"
+  echo "Error: db_name is required. Please provide a value for db_name, e.g., make clean-db db_name=flexmeasures-db [db_user=flexmeasures]"
   exit 1
 fi
 
@@ -48,11 +97,11 @@ then
   response=${response,,} # make lowercase
   if [[ "$response" =~ ^(yes|y)$ ]]; then
      delete_database $1
-     create_database $1
+     create_database $1 $2
   fi
 
 # otherwise, create a fresh database
 else
   echo "$1 does not exist"
-  create_database $1
-fi
+  create_database $1 $2
+fi