[db] close connection after executing query

pyheatpump/db.py

@@ -13,8 +13,8 @@ conn = None
 def connect():
     global conn
     if conn is None:
-        # logger.info('Will connect to database {}'.format(
-        #    config['heatpump']['database']))
+        logger.info('Will connect to database {}'.format(
+           config['heatpump']['database']))
         conn = sqlite3.connect(config['heatpump']['database'])
         conn.row_factory = sqlite3.Row
     return conn
@@ -40,6 +40,8 @@ def sql(query):
     logger.debug(f'Will execute query : \n{query}\n')
     cursor.execute(query)
 
+    conn.close()
+    logger.debug(f'Connection closed\n')
     return cursor
 
 class RowClass(object):