Map individual games to their parent game

[calisaurus]

Opposite of #41

For example:

• 'Ticket to Ride Map Collection: Volume 6 – France & Old West' | 'Ticket to Ride France' should match to Ticket to Ride
• 'Letters to Santa' should match to 'Love Letter'

Complete list TBD

[johnbeech]

Done, see:

• https://boardgames-api.calisaurus.net/api/boardgame/grids/byYear/2018 (3x5 grid)
• https://boardgames-api.calisaurus.net/api/boardgame/grids/byYear/2019 (empty grid)
• https://boardgames-api.calisaurus.net/api/boardgame/grids/byYear/2020 (3x10 grid)
• https://boardgames-api.calisaurus.net/api/boardgame/grids/byYear/2021 (21x20 grid)

[johnbeech]

Note: overall stats haven't been calculated yet - still need to do that... new ticket. Should be obvious before long.