feature #12: Add constitution Entity, repository and route

src/main/resources/sql/functions/article/upsert_article.sql

@@ -17,6 +17,9 @@ begin
     returning id into new_id;
 
     if resource->>'relations' is not null then
+        delete from article_relations
+        where source_id = (resource->>'id')::uuid;
+
         insert into article_relations (source_id, target_id, created_by_id)
         select
             (resource->>'id')::uuid,

src/main/resources/sql/functions/constitution/find_constitutions.sql

@@ -0,0 +1,42 @@
+create or replace function find_constitutions(
+    search text default null,
+    direction text default 'desc',
+    sort text default 'created_at',
+    "limit" int default 50,
+    "offset" int default 0,
+    out resource json,
+    out total int
+) language plpgsql as
+$$
+begin
+    select json_agg(t), (select count(id) from constitution)
+    into resource, total
+    from (
+        select
+            c.*,
+            find_citizen_by_id(c.created_by_id) as created_by,
+            find_constitution_titles_by_id(c.id) as titles
+        from constitution as c
+        where "search" is null or title ilike '%'||"search"||'%'
+        order by
+        case direction when 'asc' then
+            case sort
+                when 'title' then c.title
+                when 'created_at' then c.created_at::text
+                else null
+            end
+        end,
+        case direction when 'desc' then
+            case sort
+                when 'title' then c.title
+                when 'created_at' then c.created_at::text
+            end
+        end
+        desc,
+        c.created_at desc
+        limit "limit" offset "offset"
+    ) as t;
+end;
+$$;
+
+-- drop function if exists find_constitutions(json, int, int);