title: What does the 'ActiveRecord::PendingMigrationError Migrations are pending' error mean?
body: <p>I am getting this error:</p>
  
  <blockquote>
    <p>ActiveRecord::PendingMigrationError Migrations are pending. To resolve
    this issue, run: bin/rake db:migrate RAILS_ENV=development</p>
    
    <p>Extracted source (around line #392): 390 391       def
    check_pending!(connection = Base.connection) 392         raise
    ActiveRecord::PendingMigrationError if
    ActiveRecord::Migrator.needs_migration?(connection) 393       end 394
    395       def load_schema_if_pending!</p>
    
    <p>Rails.root: /Users/checkkdahustle/Desktop/Full Sail/25. Advanced
    Server-Side Languages/ASL/APP_2/Project2/ShoeDeals</p>
    
    <p>Application Trace | Framework Trace | Full Trace activerecord (4.2.5)
    lib/active_record/migration.rb:392:in <code>check_pending!' activerecord
    (4.2.5) lib/active_record/migration.rb:373:in</code>call' actionpack
    (4.2.5) lib/action_dispatch/middleware/callbacks.rb:29:in <code>block in
    call' activesupport (4.2.5) lib/active_support/callbacks.rb:88:in
    </code><strong>run_callbacks</strong>' activesupport (4.2.5)
    lib/active_support/callbacks.rb:778:in <code>_run_call_callbacks'
    activesupport (4.2.5) lib/active_support/callbacks.rb:81:in
    </code>run_callbacks' actionpack (4.2.5)
    lib/action_dispatch/middleware/callbacks.rb:27:in <code>call' actionpack
    (4.2.5) lib/action_dispatch/middleware/reloader.rb:73:in</code>call'
    actionpack (4.2.5) lib/action_dispatch/middleware/remote_ip.rb:78:in
    <code>call' actionpack (4.2.5)
    lib/action_dispatch/middleware/debug_exceptions.rb:17:in</code>call'
    web-console (2.2.1) lib/web_console/middleware.rb:39:in <code>call'
    actionpack (4.2.5)
    lib/action_dispatch/middleware/show_exceptions.rb:30:in</code>call'
    railties (4.2.5) lib/rails/rack/logger.rb:38:in <code>call_app' railties
    (4.2.5) lib/rails/rack/logger.rb:20:in</code>block in call' activesupport
    (4.2.5) lib/active_support/tagged_logging.rb:68:in <code>block in tagged'
    activesupport (4.2.5) lib/active_support/tagged_logging.rb:26:in
    </code>tagged' activesupport (4.2.5)
    lib/active_support/tagged_logging.rb:68:in <code>tagged' railties (4.2.5)
    lib/rails/rack/logger.rb:20:in</code>call' actionpack (4.2.5)
    lib/action_dispatch/middleware/request_id.rb:21:in <code>call' rack (1.6.4)
    lib/rack/methodoverride.rb:22:in</code>call' rack (1.6.4)
    lib/rack/runtime.rb:18:in <code>call' activesupport (4.2.5)
    lib/active_support/cache/strategy/local_cache_middleware.rb:28:in
    </code>call' rack (1.6.4) lib/rack/lock.rb:17:in <code>call' actionpack (4.2.5)
    lib/action_dispatch/middleware/static.rb:116:in</code>call' rack (1.6.4)
    lib/rack/sendfile.rb:113:in <code>call' railties (4.2.5)
    lib/rails/engine.rb:518:in</code>call' railties (4.2.5)
    lib/rails/application.rb:165:in <code>call' rack (1.6.4)
    lib/rack/lock.rb:17:in</code>call' rack (1.6.4)
    lib/rack/content_length.rb:15:in <code>call' rack (1.6.4)
    lib/rack/handler/webrick.rb:88:in</code>service'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/httpserver.rb:138:in
    <code>service'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/httpserver.rb:94:in
    </code>run'
    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/webrick/server.rb:295:in
    `block in start_thread'</p>
  </blockquote>