Switch to using gemspec in Gemfile.

Gemfile

@@ -1,23 +1,7 @@
 source "http://rubygems.org"
 
 # load the gem's dependencies
-# gemspec
-
-# manually load the gem's dependencies for now until
-# bundler version on Heroku is upgraded
-gem "rack",          ">= 1.0.1"
-gem "rest-client",   ">= 1.4.0", "< 1.7.0"
-gem "sequel",        "~> 3.20.0"
-gem "sinatra",       "~> 1.0.0"
-gem "sqlite3-ruby" , "~> 1.2"
-
-group :development do
-  gem "bacon"
-  gem "mocha"
-  gem "rack-test"
-  gem "rake"
-  gem "rcov"
-end
+gemspec
 
 # server-specific dependencies
 group :server do

Gemfile.lock

@@ -1,3 +1,13 @@
+PATH
+  remote: .
+  specs:
+    taps (0.3.23)
+      rack (>= 1.0.1)
+      rest-client (>= 1.4.0, < 1.7.0)
+      sequel (~> 3.20.0)
+      sinatra (~> 1.0.0)
+      sqlite3-ruby (~> 1.2)
+
 GEM
   remote: http://rubygems.org/
   specs:
@@ -10,7 +20,7 @@ GEM
     hoptoad_notifier (2.4.7)
       activesupport
       builder
-    mime-types (1.16)
+    mime-types (1.18)
     mocha (0.9.8)
       rake
     mysql (2.8.1)
@@ -21,7 +31,7 @@ GEM
       rack (>= 1.0)
     rake (0.8.7)
     rcov (0.9.9)
-    rest-client (1.6.1)
+    rest-client (1.6.7)
       mime-types (>= 1.16)
     sequel (3.20.0)
     sinatra (1.0)
@@ -43,12 +53,8 @@ DEPENDENCIES
   mysql (= 2.8.1)
   mysql2 (= 0.2.6)
   pg (= 0.9.0)
-  rack (>= 1.0.1)
   rack-test
   rake
   rcov
-  rest-client (>= 1.4.0, < 1.7.0)
-  sequel (~> 3.20.0)
-  sinatra (~> 1.0.0)
-  sqlite3-ruby (~> 1.2)
+  taps!
   thin (> 1.2.0)