Self-Vote for Staking (among others.) (#2078)

* initial doc for the staking module

* Remove md style links.

* Remove todos.

* Add rust code types

* Rename and fix review notes.

* Add new md file

* Final touches.

* Migrate compleatly to rustdoc

* Update link

* Fix heading

* Final touches wrt the new template.

* Remove empty prereq.

* Fix more reviews

* Some final nits.

* Fix some side issues.

* Fix another set of reviews

* Fix + stabilize leftover reivews.

* Remove unused test parameters

* Fix typo.

* Merge redundant loops

* Adds phantom self-vote

* Fix broken tests.

* Refactor some names to match the reference.

* Remove redundant inner loops from election round.

* Introduce phragmen post-processing.

* Some fixes and todos.

* Fix some tests with new phragmen params

* Fix test

* Bump spec

* Fix wasm build

* Fix tests and phragmen fallback. Avoid double-controlling

* Fix and rebuild wasm

* Whitespaces, whitespaces everywhere.

* Rebuild

* Disable post-processing.

* Identify by stash, not controller account.

* Couple of fixes

* Fix first test

* Fix invulnerability_should_work

* Fix a couple more tests

* Fix more tests

* Fix more tests

* Fix more tests

* Fix some tests

* Fix update-ledger.

* Fix update-ledger.

* Fix another test

* Fix another test

* Fix rest of staking tests

* Remove printlns

* Rebuild wasm

* Fix & tests for auth/val syncing

* Fix up threading for tests

* Remove superfluous asserts

substrate/srml/consensus/src/lib.rs

@@ -244,6 +244,12 @@ impl<T: Trait> Module<T> {
 		}
 	}
 
+	/// Set a single authority by index.
+	pub fn set_authority_count(count: u32) {
+		Self::save_original_authorities(None);
+		AuthorityStorageVec::<T::SessionKey>::set_count(count);
+	}
+
 	/// Set a single authority by index.
 	pub fn set_authority(index: u32, key: &T::SessionKey) {
 		let current_authority = AuthorityStorageVec::<T::SessionKey>::item(index);