Add branch_name to Dast::Profile

What does this MR do?

adds new field branch_name to dast_profiles.

Why?

we would like to be able to specify which branch is used when running an on-demand dast scan.

Related Issue(s)

• #322526 (closed)

Database

Migrations

% rake db:migrate && rake db:rollback                                                                                                                                                                                                                                                                                                                                           
== 20210223053451 AddBranchNameToDastProfile: migrating =======================
-- add_column(:dast_profiles, :branch_name, :text)
   -> 0.0016s
-- transaction_open?()
   -> 0.0000s
-- current_schema()
   -> 0.0003s
-- execute("ALTER TABLE dast_profiles\nADD CONSTRAINT check_6c9d775949\nCHECK ( char_length(branch_name) <= 255 )\nNOT VALID;\n")
   -> 0.0013s
-- current_schema()
   -> 0.0002s
-- execute("SET statement_timeout TO 0")
   -> 0.0009s
-- execute("ALTER TABLE dast_profiles VALIDATE CONSTRAINT check_6c9d775949;")
   -> 0.0435s
-- execute("RESET ALL")
   -> 0.0008s
== 20210223053451 AddBranchNameToDastProfile: migrated (0.0631s) ==============

== 20210223053451 AddBranchNameToDastProfile: reverting =======================
-- remove_column(:dast_profiles, :branch_name)
   -> 0.0011s
== 20210223053451 AddBranchNameToDastProfile: reverted (0.0053s) ==============

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team