Add tables for member management (#65)

Members table and and other related tables

We should also add indexes and comments and roles.
We should also `ALTER registration_requests` with `approved/denied`
field

---------

[anonymized]

gray-whale/migrations/V4__members_table.sql

@@ -0,0 +1,76 @@
+CREATE TABLE members
+	 ( id UUID PRIMARY KEY DEFAULT UUID_GENERATE_V4()
+     -- incremental number that is also used as variable symbol for payments
+	 , member_number INT NOT NULL
+	 , email TEXT NOT NULL
+	 , last_name TEXT
+	 , first_name TEXT
+	 , created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+	 , left_at TIMESTAMPTZ
+	 , date_of_birth DATE
+	 , address TEXT
+	 , city TEXT
+	 , postal_code TEXT
+	 , language TEXT
+	 , phone_number TEXT
+	 , registration_request_id UUID REFERENCES registration_requests(id)
+	 );
+
+create index member_member_number on members(member_number);
+create index member_email on members(email);
+create index member_last_name on members(last_name);
+create index member_first_name on members(first_name);
+create index member_city on members(city);
+create index member_postal_code on members(postal_code);
+create index member_created_at on members(created_at);
+
+comment on column members.member_number is 'Incremental number that is also used as variable symbol in bank transfers';
+
+CREATE TABLE workplaces
+	( id UUID PRIMARY KEY DEFAULT UUID_GENERATE_V4()
+	, created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+	, name TEXT NOT NULL
+	, chairperson_id UUID NOT NULL REFERENCES members(id)
+	);
+
+create index workplace_created_at on workplaces(created_at);
+create index workplace_name on workplaces(name);
+
+comment on column workplaces.chairperson_id is 'Id of union member who in role of chairpeson of workplace';
+
+ALTER TABLE members
+    ADD COLUMN workplace_id UUID REFERENCES workplaces(id);
+
+CREATE TABLE occupations
+	( id UUID PRIMARY KEY DEFAULT UUID_GENERATE_V4()
+	, created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+	, company_name TEXT
+	, position TEXT
+	, member_id UUID REFERENCES members(id)
+	);
+
+create index occupations_created_at on occupations(created_at);
+create index occupations_company_name on occupations(company_name);
+
+comment on column occupations.company_name is 'Company name filled by member. This is free text that can later be normalized further';
+comment on column occupations.position is 'Job position filled by member. This is free text that can later be normalized further';
+
+CREATE TABLE registration_events
+	( id UUID PRIMARY KEY DEFAULT UUID_GENERATE_V4()
+	, created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+	, registration_request_id UUID REFERENCES registration_requests(id)
+    --Id of user who initiated that event (eg. called with new member, added them to mailing list, etc)
+	, initiator_id UUID REFERENCES members(id)
+	, type INT
+	, note TEXT
+	);
+
+create index registration_event_created_at on registration_events(created_at);
+create index registration_event_registration_request_id on registration_events(registration_request_id);
+create index registration_event_initiator_id on registration_events(initiator_id);
+create index registration_event_type on registration_events(type);
+
+comment on column registration_events.registration_request_id is 'All registration events should be connected to some registration request';
+comment on column registration_events.initiator_id is 'Id of user who initiated that event (eg. called with new member, added them to mailing list, etc)';
+comment on column registration_events.type is 'Type is enum of predefined steps of user onboarding';
+comment on column registration_events.note is 'Note is free text that can initiator add to any registration event. Comment, practical info, etc.';