change datatype of merge_requests.squash_commit_sha to binary

app/models/merge_request.rb

@@ -16,6 +16,9 @@ class MergeRequest < ApplicationRecord
   include ReactiveCaching
   include FromUnion
   include DeprecatedAssignee
+  include ShaAttribute
+
+  sha_attribute :squash_commit_sha
 
   self.reactive_cache_key = ->(model) { [model.project.id, model.iid] }
   self.reactive_cache_refresh_interval = 10.minutes

db/migrate/20191013100213_add_squash_commit_sha_to_merge_requests.rb

@@ -5,6 +5,6 @@ class AddSquashCommitShaToMergeRequests < ActiveRecord::Migration[5.2]
   DOWNTIME = false
 
   def change
-    add_column :merge_requests, :squash_commit_sha, :varchar
+    add_column :merge_requests, :squash_commit_sha, :binary
   end
 end

db/schema.rb

@@ -2258,7 +2258,7 @@ ActiveRecord::Schema.define(version: 2019_10_16_072826) do
     t.boolean "allow_maintainer_to_push"
     t.integer "state_id", limit: 2
     t.string "rebase_jid"
-    t.string "squash_commit_sha"
+    t.binary "squash_commit_sha"
     t.index ["assignee_id"], name: "index_merge_requests_on_assignee_id"
     t.index ["author_id"], name: "index_merge_requests_on_author_id"
     t.index ["created_at"], name: "index_merge_requests_on_created_at"