Add basic API, only with system endpoints

PluralKit.Core/db_schema.sql

@@ -0,0 +1,69 @@
+create table if not exists systems
+(
+    id          serial primary key,
+    hid         char(5) unique not null,
+    name        text,
+    description text,
+    tag         text,
+    avatar_url  text,
+    token       text,
+    created     timestamp      not null default (current_timestamp at time zone 'utc'),
+    ui_tz       text           not null default 'UTC'
+);
+
+create table if not exists members
+(
+    id          serial primary key,
+    hid         char(5) unique not null,
+    system      serial         not null references systems (id) on delete cascade,
+    color       char(6),
+    avatar_url  text,
+    name        text           not null,
+    birthday    date,
+    pronouns    text,
+    description text,
+    prefix      text,
+    suffix      text,
+    created     timestamp      not null default (current_timestamp at time zone 'utc')
+);
+
+create table if not exists accounts
+(
+    uid    bigint primary key,
+    system serial not null references systems (id) on delete cascade
+);
+
+create table if not exists messages
+(
+    mid     bigint primary key,
+    channel bigint not null,
+    member  serial not null references members (id) on delete cascade,
+    sender  bigint not null
+);
+
+create table if not exists switches
+(
+    id        serial primary key,
+    system    serial    not null references systems (id) on delete cascade,
+    timestamp timestamp not null default (current_timestamp at time zone 'utc')
+);
+
+create table if not exists switch_members
+(
+    id     serial primary key,
+    switch serial not null references switches (id) on delete cascade,
+    member serial not null references members (id) on delete cascade
+);
+
+create table if not exists webhooks
+(
+    channel bigint primary key,
+    webhook bigint not null,
+    token   text   not null
+);
+
+create table if not exists servers
+(
+    id          bigint primary key,
+    log_channel bigint
+);