由于Heroku似乎不支持MySQL，我正在尝试构建他们的项目，将我的MySql数据库转换为PostgreSQL，每https://devcenter.heroku.com/articles/heroku-mysql。但是，我收到了这个错误：
SELECT dateTime::DATE, usage, SUM(usage) FROM tableName GROUP BY dateTime::DATE, lngusage;我不知道这意味着什么，并且在localhost:mysql2postgres davea$ mysqltopostgres
/Users/davea/.rvm/gems/ruby-2.1.7@global/gems/bundler-1.11.2/lib/bundler/runtime.rb:34:in `block in setup': You have already activated test-unit 2.1.7.0, but your Gemfile requires test-unit 3.1.7. Prepending `bundle exec` to your command may solve this. (Gem::LoadError)
from /Users/davea/.rvm/gems/ruby-2.1.7@global/gems/bundler-1.11.2/lib/bundler/runtime.rb:19:in `setup'
from /Users/davea/.rvm/gems/ruby-2.1.7@global/gems/bundler-1.11.2/lib/bundler.rb:92:in `setup'
from /Users/davea/.rvm/gems/ruby-2.1.7@global/gems/bundler-1.11.2/lib/bundler/setup.rb:8:in `<top (required)>'
from /Users/davea/.rvm/rubies/ruby-2.1.7/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require'
from /Users/davea/.rvm/rubies/ruby-2.1.7/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require'
from /Users/davea/.rvm/gems/ruby-2.1.7@global/gems/mysqltopostgres-0.3.0/bin/mysqltopostgres:5:in `<top (required)>'
from /Users/davea/.rvm/rubies/ruby-2.1.7/bin/mysqltopostgres:23:in `load'
from /Users/davea/.rvm/rubies/ruby-2.1.7/bin/mysqltopostgres:23:in `<main>'
from /Users/davea/.rvm/gems/ruby-2.1.7/bin/ruby_executable_hooks:15:in `eval'
from /Users/davea/.rvm/gems/ruby-2.1.7/bin/ruby_executable_hooks:15:in `<main>'
前面运行相同的命令并不能解决问题。