Resolve conflicts in development documentation

Signed-off-by: Rémy Coutable <remy@rymai.me>

doc/development/README.md

@@ -13,10 +13,7 @@
 - [Generate a changelog entry with `bin/changelog`](changelog.md)
 - [Code review guidelines](code_review.md) for reviewing code and having code reviewed.
 - [Limit conflicts with EE when developing on CE](limit_ee_conflicts.md)
-<<<<<<< HEAD
 - [Guidelines for implementing Enterprise Edition feature](ee_features.md)
-=======
->>>>>>> upstream/master
 
 ## UX and frontend guides
 
@@ -61,29 +58,15 @@
 
 - [Merge Request checklist](database_merge_request_checklist.md)
 - [Adding database indexes](adding_database_indexes.md)
-<<<<<<< HEAD
-- [Post Deployment Migrations](post_deployment_migrations.md)
-- [Foreign keys & associations](foreign_keys.md)
-- [Serializing data](serializing_data.md)
-- [Polymorphic associations](polymorphic_associations.md)
-- [Single table inheritance](single_table_inheritance.md)
-- [Background Migrations](background_migrations.md)
-=======
 - [Foreign keys & associations](foreign_keys.md)
 - [Single table inheritance](single_table_inheritance.md)
 - [Polymorphic associations](polymorphic_associations.md)
 - [Serializing data](serializing_data.md)
 - [Hash indexes](hash_indexes.md)
->>>>>>> upstream/master
 - [Storing SHA1 hashes as binary](sha1_as_binary.md)
 - [Iterating tables in batches](iterating_tables_in_batches.md)
 - [Ordering table columns](ordering_table_columns.md)
 - [Verifying database capabilities](verifying_database_capabilities.md)
-<<<<<<< HEAD
-- [Hash indexes](hash_indexes.md)
-- [Swapping Tables](swapping_tables.md)
-=======
->>>>>>> upstream/master
 
 ## Documentation guides
 

doc/development/testing_guide/testing_levels.md

@@ -67,11 +67,7 @@ run JavaScript tests, so you can either run unit tests (e.g. test a single
 JavaScript method), or integration tests (e.g. test a component that is composed
 of multiple components).
 
-<<<<<<< HEAD
-## System tests or Feature tests
-=======
 ## System tests or feature tests
->>>>>>> upstream/master
 
 Formal definition: https://en.wikipedia.org/wiki/System_testing.
 
@@ -112,11 +108,7 @@ The reasons why we should follow these best practices are as follows:
 [Poltergeist]: https://github.com/teamcapybara/capybara#poltergeist
 [RackTest]: https://github.com/teamcapybara/capybara#racktest
 
-<<<<<<< HEAD
-## Black-box tests or End-to-end tests
-=======
 ## Black-box tests or end-to-end tests
->>>>>>> upstream/master
 
 GitLab consists of [multiple pieces] such as [GitLab Shell], [GitLab Workhorse],
 [Gitaly], [GitLab Pages], [GitLab Runner], and GitLab Rails. All theses pieces
@@ -139,13 +131,10 @@ always in-sync with the codebase.
 [GitLab QA]: https://gitlab.com/gitlab-org/gitlab-qa
 [part of GitLab Rails]: https://gitlab.com/gitlab-org/gitlab-ce/tree/master/qa
 
-<<<<<<< HEAD
 ## EE-specific tests
 
 EE-specific tests follows the same organization, but under the `spec/ee` folder.
 
-=======
->>>>>>> upstream/master
 ## How to test at the correct level?
 
 As many things in life, deciding what to test at each level of testing is a