Create game contributors model and update individual game page

[samjjacko]

To associate members with their games in the individual game pages, we need to add the following table:
GameContributors:

• uuid game (foreign key to game.id, pk)
• uuid member (foreign key to member.id, pk)
• varchar role

The game page should feature a list of all of the contributing member's names, and links to their respective member pages on the site (e.g. /member/12). Individual member pages do not need to be implemented before this; as long as it routes correctly.

[github-actions]

Branch issue-18-Create_game_contributors_model_and_update_individual_game_page created!