Die automatisch generierte Rails-Migration verursacht einen "Syntaxfehler, unerwartet '\ n" "Fehler

Question

Ich verwende Rails 4.2.3. Ich habe diese Migration geschaffen, die für mich automatisch generiert wurde von Rails ...

class CreateDistanceUnits < ActiveRecord::Migration 
    def change 
    create_table :distance_units do |t| 
     t.string, :description 
     t.string :abbrev 
     t.timestamps null: false 
    end 
    add_index :distance_units, [:abbrev], :unique => true 
    end 
end 

aber wenn ich es laufen, bekomme ich diese bizarren Fehler

davea$ rake db:migrate 
rake aborted! 
SyntaxError: /Users/davea/Documents/workspace/runtrax/db/migrate/20160629210722_create_distance_units.rb:4: syntax error, unexpected '\n', expecting &. or :: or '[' or '.' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activesupport-4.2.5.1/lib/active_support/dependencies.rb:244:in `rescue in load_dependency' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activesupport-4.2.5.1/lib/active_support/dependencies.rb:237:in `load_dependency' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activesupport-4.2.5.1/lib/active_support/dependencies.rb:274:in `require' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:777:in `load_migration' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:773:in `migration' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:768:in `disable_ddl_transaction' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:1051:in `use_transaction?' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:1043:in `ddl_transaction' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:997:in `execute_migration_in_transaction' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:959:in `block in migrate' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:955:in `each' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:955:in `migrate' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:823:in `up' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/migration.rb:801:in `migrate' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/tasks/database_tasks.rb:137:in `migrate' 
/Users/davea/.rvm/gems/ruby-2.3.0@global/gems/activerecord-4.2.5.1/lib/active_record/railties/databases.rake:44:in `block (2 levels) in <top (required)>' 
/Users/davea/.rvm/gems/ruby-2.3.0/gems/rake-11.2.2/exe/rake:27:in `<top (required)>' 
/Users/davea/.rvm/gems/ruby-2.3.0/bin/ruby_executable_hooks:15:in `eval' 
/Users/davea/.rvm/gems/ruby-2.3.0/bin/ruby_executable_hooks:15:in `<main>' 

Was es über beschwert? Ich benutze eine PostGres-Datenbank. Danke, - Dave

Answer 1

die Sie interessieren, ob es funktionieren

class CreateDistanceUnits < ActiveRecord::Migration 
    def change 
    create_table :distance_units do |t| 
     t.string :description 
     t.string :abbrev 
     t.timestamps null: false 
    end 
    add_index :distance_units, [:abbrev], :unique => true 
    end 
end 

Es ist unerwartet , in der Migration vor :description