bundle: put mysql, pg and ruby-debug in groups

Useful so bundle can be installed without those gems, which are all optional

Gemfile

@@ -12,5 +12,6 @@ gem 'mocha', '~> 0.9.8'
 gem 'sqlite3-ruby', '~> 1.2.5'
 gem 'dm-core', '~> 0.10.2'
 gem 'do_sqlite3', '~> 0.10.1.1'
-gem 'mysql', '~> 2.8.1'
-gem 'pg', '~> 0.8.0'
+gem 'mysql', '~> 2.8.1', :group => :mysql
+gem 'pg', '~> 0.8.0', :group => :pg
+gem 'ruby-debug', '~> 0.10.3', :group => :debug

Gemfile.lock

@@ -29,6 +29,7 @@ GEM
     arel (0.4.0)
       activesupport (>= 3.0.0.beta)
     builder (2.1.2)
+    columnize (0.3.1)
     data_objects (0.10.1)
       addressable (~> 2.1)
     dm-core (0.10.2)
@@ -40,6 +41,7 @@ GEM
       abstract (>= 1.0.0)
     extlib (0.9.15)
     i18n (0.4.1)
+    linecache (0.43)
     mocha (0.9.8)
       rake
     mysql (2.8.1)
@@ -51,6 +53,11 @@ GEM
       rack (>= 1.0)
     rake (0.8.7)
     rspec (1.3.0)
+    ruby-debug (0.10.3)
+      columnize (>= 0.1)
+      ruby-debug-base (~> 0.10.3.0)
+    ruby-debug-base (0.10.3)
+      linecache (>= 0.3)
     sequel (3.8.0)
     sqlite3-ruby (1.2.5)
     tzinfo (0.3.22)
@@ -68,5 +75,6 @@ DEPENDENCIES
   mysql (~> 2.8.1)
   pg (~> 0.8.0)
   rspec (~> 1.3.0)
+  ruby-debug (~> 0.10.3)
   sequel (~> 3.8.0)
   sqlite3-ruby (~> 1.2.5)