Fix rebase commit SHA migration namefix-ce-migration-timestamp

This already existed in EE with a different timestamp, so rename for CE and make
it idempotent.

2 files changed, 15 insertions, 7 deletions

diff --git a/db/migrate/20171230123729_add_rebase_commit_sha_to_merge_requests.rb b/db/migrate/20171230123729_add_rebase_commit_sha_to_merge_requests.rb
deleted file mode 100644
index 2ce156fa92e..00000000000
--- a/db/migrate/20171230123729_add_rebase_commit_sha_to_merge_requests.rb
+++ /dev/null
@@ -1,7 +0,0 @@
-class AddRebaseCommitShaToMergeRequests < ActiveRecord::Migration
-  DOWNTIME = false
-
-  def change
-    add_column :merge_requests, :rebase_commit_sha, :string
-  end
-end
diff --git a/db/migrate/20171230123729_add_rebase_commit_sha_to_merge_requests_ce.rb b/db/migrate/20171230123729_add_rebase_commit_sha_to_merge_requests_ce.rb
new file mode 100644
index 00000000000..94a7c1019d8
--- /dev/null
+++ b/db/migrate/20171230123729_add_rebase_commit_sha_to_merge_requests_ce.rb
@@ -0,0 +1,15 @@
+class AddRebaseCommitShaToMergeRequestsCe < ActiveRecord::Migration
+  DOWNTIME = false
+
+  def up
+    unless column_exists?(:merge_requests, :rebase_commit_sha)
+      add_column :merge_requests, :rebase_commit_sha, :string
+    end
+  end
+
+  def down
+    if column_exists?(:merge_requests, :rebase_commit_sha)
+      remove_column :merge_requests, :rebase_commit_sha
+    end
+  end
+end