fixed the create database part of postgresql.py (#1072)

Author: pUrGe12

nettacker/database/postgresql.py

@@ -10,7 +10,6 @@ def postgres_create_database():
     when using postgres database, this is the function that is used to
     create the database for the first time when you the nettacker run module.
     """
-
     try:
         engine = create_engine(
             "postgresql+psycopg2://{username}:{password}@{host}:{port}/{name}".format(
@@ -21,15 +20,14 @@ def postgres_create_database():
     except OperationalError:
         # if the database does not exist
         engine = create_engine(
-            "postgresql+psycopg2://{username}:{password}@{host}:{port}/{name}".format(
+            "postgresql+psycopg2://{username}:{password}@{host}:{port}/postgres".format(
                 **Config.db.as_dict()
             )
         )
         conn = engine.connect()
-        conn.execute("commit")
+        conn = conn.execution_options(isolation_level="AUTOCOMMIT")
         conn.execute(text(f"CREATE DATABASE {Config.db.name}"))
         conn.close()
-
         engine = create_engine(
             "postgresql+psycopg2://{username}:{password}@{host}:{port}/{name}".format(
                 **Config.db.as_dict()