static async delete(proxyID, userID) {
        const bean = await R.findOne("proxy", " id = ? AND user_id = ? ", [ proxyID, userID ]);

        if (!bean) {
            throw new Error("proxy not found");
        }

        // Delete removed proxy from monitors if exists
        await R.exec("UPDATE monitor SET proxy_id = null WHERE proxy_id = ?", [ proxyID ]);

        // Delete proxy from list
        await R.trash(bean);
    }
Deletes proxy with given id and removes it from monitors
@param {number} proxyID ID of proxy to delete
@param {number} userID ID of proxy owner
@returns {Promise<void>}