Allow browsers to load table OPTIONS after preflight

Fixes #51
Merge pull request #57 from begriffs/cors-info-body

Allow browsers to load table OPTIONS after preflight
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And ignoring anvil build artifacts
Merge pull request #59 from begriffs/slack

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WIP: feature specs for auth
WIP: Trap postgres errors in middleware

Fixes #39
Remove "public" schema pollution from fixture
Remove stray role in schema
Make tests pending and revisit after Friday deadline
Merge pull request #60 from begriffs/auth-feature-specs

Auth feature specs
add table with fk for testing.
simple unit tests for existing functionality
data/procedure for foreign key
return a map of foreign keys
getting foreign key data with a column.
some more setup/teardown actions
fix test to reflect more tables
fix basic auth parsing
clean up spec helper
emit references for columns with foreign keys