import re


def find_keywords(df, reg_dict):
    """
    Per domain in `reg_dict`, find all matches for the "joined domain regex" in the `all_text` column of the dataframe. Store the matches in a column with the domain name.

    Parameters
    ----------
    df: DataFrame
        dataframe with the column `all_text`
    reg_dict: dict
        dictionary with domains as keys and a "joined domain regex" as values

    Returns
    -------
    DataFrame
        dataframe with the new columns containing matches
    """
    for k, v in reg_dict.items():
        df[k] = df.all_text.str.findall(v, flags=re.IGNORECASE)
    return df