Add description and roll_over to IterationsCadences

What does this MR do?

Adds description and roll_over fields to IterationsCadence. Create and update mutation support both new fields.

Relates to #329243 (closed)

Migration output

Migrate

== 20210427194958 AddDescriptionRollOverToIterationsCadences: migrating =======
-- add_column(:iterations_cadences, :roll_over, :boolean, {:null=>false, :default=>false})
   -> 0.0027s
-- add_column(:iterations_cadences, :description, :text)
   -> 0.0008s
== 20210427194958 AddDescriptionRollOverToIterationsCadences: migrated (0.0113s)

== 20210427200840 AddTextLimitToIterationsCadencesDescription: migrating ======
-- transaction_open?()
   -> 0.0000s
-- current_schema()
   -> 0.0002s
-- execute("ALTER TABLE iterations_cadences\nADD CONSTRAINT check_5c5d2b44bd\nCHECK ( char_length(description) <= 5000 )\nNOT VALID;\n")
   -> 0.0010s
-- current_schema()
   -> 0.0002s
-- execute("SET statement_timeout TO 0")
   -> 0.0005s
-- execute("ALTER TABLE iterations_cadences VALIDATE CONSTRAINT check_5c5d2b44bd;")
   -> 0.0010s
-- execute("RESET ALL")
   -> 0.0006s
== 20210427200840 AddTextLimitToIterationsCadencesDescription: migrated (0.0104s)

Rollback

== 20210427200840 AddTextLimitToIterationsCadencesDescription: reverting ======
-- execute("ALTER TABLE iterations_cadences\nDROP CONSTRAINT IF EXISTS check_5c5d2b44bd\n")
   -> 0.0011s
== 20210427200840 AddTextLimitToIterationsCadencesDescription: reverted (0.0062s)

== 20210427194958 AddDescriptionRollOverToIterationsCadences: reverting =======
-- remove_column(:iterations_cadences, :roll_over)
   -> 0.0023s
-- remove_column(:iterations_cadences, :description)
   -> 0.0008s
== 20210427194958 AddDescriptionRollOverToIterationsCadences: reverted (0.0062s)

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Related to #329243 (closed)