Don't generate default metadata value for MySQL. Closes #16
Add documentation about using PostgreSQL JSON column type
Merge pull request #70 from j-manu/postgres-json-doc

Add documentation about using PostgreSQL JSON column type
Raise error when no transition to states are provided.
Correcting typo in raised error.
Corrected `:nil` to `nil` in transition specs.
Merge pull request #72 from gocardless/fix-empty-array-to-state

Raise error when no transition to states are provided.
v0.8.1
Avoid repeated SQL lookups for current_state whilst looping through each possible event
Merge branch 'master' into mysql-default

Conflicts:
	lib/generators/statesman/active_record_transition_generator.rb
	lib/generators/statesman/migration_generator.rb
Rename #is_mysql? > #mysql?
Merge pull request #19 from gocardless/mysql-default

Don't generate default metadata value for MySQL
v0.8.2
Merge pull request #76 from pacso/master

Avoid repeated SQL lookups for current_state
v0.8.3
Remove duplication from adding transition logic
Merge pull request #81 from gocardless/de-duplicating

Remove duplication from adding transition logic
Allow adding callbacks against multiple to states, and bump rubocop
Bump versions
Merge pull request #84 from gocardless/update-dependencies

Update dependencies