title: Cannot Migrate with taps ERROR: Rack::Utils::OkJson::Error
body: <p>I'm trying to migrate my rails database from sqlite3 to postgresql so I can push to heroku. I'm trying to migrate the data as well.<br/>
  Here is my gemfile:</p>
  
  <pre><code>source 'https://rubygems.org'
  
  
  # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
  gem 'rails', '4.2.5'
  # Use sqlite3 as the database for Active Record
  
  gem 'sqlite3'
  gem 'pg'
  # Use SCSS for stylesheets
  gem 'sass-rails', '~&gt; 5.0'
  # Use Uglifier as compressor for JavaScript assets
  gem 'uglifier', '&gt;= 1.3.0'
  # Use CoffeeScript for .coffee assets and views
  gem 'coffee-rails', '~&gt; 4.1.0'
  # See https://github.com/rails/execjs#readme for more supported runtimes
  # gem 'therubyracer', platforms: :ruby
  
  gem 'taps', '&gt;= 0.3.22'
  gem "tilt", '~&gt; 1.4.1'
  # Use jquery as the JavaScript library
  gem 'jquery-rails'
  # Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
  gem 'turbolinks'
  # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
  gem 'jbuilder', '~&gt; 2.0'
  # bundle exec rake doc:rails generates the API under doc/api.
  gem 'sdoc', '~&gt; 0.4.0', group: :doc
  
  # Use ActiveModel has_secure_password
  gem 'bcrypt', '~&gt; 3.1.7'
  gem "twitter-bootstrap-rails"
  # Use Unicorn as the app server
  # gem 'unicorn'
  gem 'therubyracer'
  gem 'bootstrap-sass'
  
  gem 'will_paginate', '~&gt; 3.1.0'
  
  
  # Use Capistrano for deployment
  # gem 'capistrano-rails', group: :development
  
  group :development, :test do
    # Call 'byebug' anywhere in the code to stop execution and get a debugger console
    gem 'byebug'
  end
  
  group :development do
    # Access an IRB console on exception pages or by using &lt;%= console %&gt; in views
    gem 'web-console', '~&gt; 2.0'
  
    # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
    gem 'spring'
  
  end
  
  group :production do
  
    gem 'rails_12factor'
    gem 'puma'
  
  end
  </code></pre>
  
  <p>I also changed my database.yml file to migrate to postgres</p>
  
  <pre><code>development:
    adapter: postgresql
    encoding: unicode
    database: gainxp_development
    pool: 5
    username: sam
    password: pass
    host: localhost
  
  
  # Warning: The database defined as "test" will be erased and
  # re-generated from your development database when you run "rake".
  # Do not set this db to the same as development or production.
  test:
    adapter: postgresql
    encoding: unicode
    database: gainxp_test
    pool: 5
    username: sam
    password: pass
    host: localhost
  
  production:
    adapter: postgresql
    encoding: unicode
    database: gainxp_production
    pool: 5 
    username: sam
    password: pass
    host: localhost
  </code></pre>
  
  <p>I ran the following command to start my taps server and it started correctly:</p>
  
  <pre><code>taps server sqlite://db/development.sqlite3 sam pass -p $PORT 
  </code></pre>
  
  <p>In a different terminal I ran:</p>
  
  <pre><code>sudo taps pull postgres://sam:pass@localhost/gainxp_development http://sam:pass@localhost:$PORT
  </code></pre>
  
  <p>Which gave me this error:</p>
  
  <pre><code>Receiving schema
  Unable to fetch tables information from http://sam:pass@0.0.0.0:8080. Please check the server log.
  </code></pre>
  
  <p>My pg_hba.conf file is the following</p>
  
  <pre><code># DO NOT DISABLE!
  # If you change this first entry you will need to make sure that the
  # database superuser can access the database using some other method.
  # Noninteractive access to all databases is required during automatic
  # maintenance (custom daily cronjobs, replication, and similar tasks).
  #
  # Database administrative login by Unix domain socket
  local   all             postgres                                trust
  
  
  # TYPE  DATABASE        USER            ADDRESS                 METHOD
  
  # "local" is for Unix domain socket connections only
  local   all             all                                     trust
  # IPv4 local connections:
  host    all             all             127.0.0.1/32            md5
  # IPv6 local connections:
  host    all             all             ::1/128                 md5
  # Allow replication connections from localhost, by a user with the
  # replication privilege.
  #local   replication     postgres                                peer
  #host    replication     postgres        127.0.0.1/32            md5
  #host    replication     postgres        ::1/128                 md5
  </code></pre>
  
  <p>When I visit the sinatra server taps is running on, I get the following appear on a white  background: </p>
  
  <pre><code>Taps &gt;= v0.3.22 is required for this server    
  </code></pre>
  
  <p>I've been at this for weeks trying to migrate my db. Thanks for the help</p>