当我输入命令行时，heroku在Nitrous.IO中运行rake db：migrate。 这就是它在控制台中显示的内容。:-（非常沮丧。
action@naomi-box-1-129907:~/pinteresting(master*)$ heroku run rake db:migrate
/home/action/.heroku/client/vendor/gems/json-1.7.7/lib/json/common.rb:67:in `initialize': no implicit conversion of nil into Hash (TypeError)
from /home/action/.heroku/client/vendor/gems/json-1.7.7/lib/json/common.rb:67:in `new'
from /home/action/.heroku/client/vendor/gems/json-1.7.7/lib/json/common.rb:67:in `generator='
from /home/action/.heroku/client/vendor/gems/json-1.7.7/lib/json/ext.rb:17:in `<module:Ext>'
from /home/action/.heroku/client/vendor/gems/json-1.7.7/lib/json/ext.rb:12:in `<module:JSON>'
from /home/action/.heroku/client/vendor/gems/json-1.7.7/lib/json/ext.rb:9:in `<top (required)>'
from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/action/.heroku/client/vendor/gems/json-1.7.7/lib/json.rb:58:in `<module:JSON>'
from /home/action/.heroku/client/vendor/gems/json-1.7.7/lib/json.rb:54:in `<top (required)>'
from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/action/.heroku/client/lib/heroku/cli.rb:18:in `<top (required)>'
from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/action/.parts/packages/ruby2.1/2.1.1/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /home/action/.parts/bin/heroku:22:in `<main>'
我有什么办法可以解决这个问题吗？或者我应该创建另一个框并重做所有内容？