Allow bigint annotations in rails 4. (#569)

In rails 4, columns do not respond to `bigint?`.  However, in both rails
4 and rails 5, columns do respond to `sql_type`. This way, annotations
should work in both versions.

Author: siegfault

lib/annotate/annotate_models.rb

@@ -62,7 +62,7 @@ module AnnotateModels
 
   # Don't show limit (#) on these column types
   # Example: show "integer" instead of "integer(4)"
-  NO_LIMIT_COL_TYPES = %w(integer boolean).freeze
+  NO_LIMIT_COL_TYPES = %w(integer bigint boolean).freeze
 
   # Don't show default value for these column types
   NO_DEFAULT_COL_TYPES = %w(json jsonb hstore).freeze
@@ -362,7 +362,7 @@ def get_index_info(klass, options = {})
     end
 
     def get_col_type(col)
-      if col.respond_to?(:bigint?) && col.bigint?
+      if (col.respond_to?(:bigint?) && col.bigint?) || /\Abigint\b/.match?(col.sql_type)
         'bigint'
       else
         (col.type || col.sql_type).to_s

spec/annotate/annotate_models_spec.rb

@@ -52,7 +52,8 @@ def mock_column(name, type, options = {})
     default_options = {
       limit: nil,
       null: false,
-      default: nil
+      default: nil,
+      sql_type: type
     }
 
     stubs = default_options.dup
@@ -184,6 +185,7 @@ def mock_column(name, type, options = {})
                          mock_column(:id, :integer),
                          mock_column(:integer, :integer, unsigned?: true),
                          mock_column(:bigint,  :integer, unsigned?: true, bigint?: true),
+                         mock_column(:bigint,  :bigint,  unsigned?: true),
                          mock_column(:float,   :float,   unsigned?: true),
                          mock_column(:decimal, :decimal, unsigned?: true, precision: 10, scale: 2),
                        ])
@@ -196,6 +198,7 @@ def mock_column(name, type, options = {})
 #  id      :integer          not null
 #  integer :integer          unsigned, not null
 #  bigint  :bigint           unsigned, not null
+#  bigint  :bigint           unsigned, not null
 #  float   :float            unsigned, not null
 #  decimal :decimal(10, 2)   unsigned, not null
 #