Contributor only added to resources

# Summary

When creating a resource the bot is correctly including the contributor when submitting to AirTable.
This is not happening for the other tables where there is a contributor field.

# Existing behaviour

When executing the following commands the contributor is not submitted to AirTable:-

- /add-author
- /add-tag
- /add-category
- /add-blockchain
- /add-glossary

It is also possible to execute these commands without being listed as a contributor.

# Expected behaviour

When executing the commands listed above the bot should check if the user is a contributor and ask them to add themselves before trying again.

Once the user executes the commands and is found in the contributor table they should be able to complete the commands as usual and they should be added to the relevant column when storing the new information.

Each of the tables updated by the commands listed above have a `Contributor` column, which is a reference to the `Contributor` table.