:bug: add error type for name conflicts

server/src/server/auth/sql.gleam

···
   GetRoleRow(user_role: UserRoleEnum)
 }
 
-/// Runs the `get_role` query
-/// defined in `./src/server/auth/sql/get_role.sql`.
+///   Find role assigned to an determined user
 ///
 /// > 🐿️ This function was generated automatically using v4.6.0 of
 /// > the [squirrel package](https://github.com/giacomocavalieri/squirrel).
···
     decode.success(GetRoleRow(user_role:))
   }
 
-  "select u.user_role from public.user_account as u
+  "--   Find role assigned to an determined user
+select u.user_role
+from public.user_account as u
 where u.id = $1;
 "
   |> pog.query

server/src/server/crew.gleam

···
 import gleam/result
 import pog
 import server/crew/sql
-import server/user as server_user
+import server/user
 import shared/crew.{type Crew, Crew}
-import shared/user.{type User, User}
+import shared/user.{type User, User} as _shared_user
 
 pub type CrewError {
   Database(pog.QueryError)
-  UserError(server_user.UserError)
+  UserError(user.UserError)
+
+  /// Crew name needs to be unique
+  NameConflict
+  /// Crew not found
   NotFound
 }
 
+/// Register an new empty crew
 pub fn register(
   db db: pog.Connection,
   leader leader: User,
···
   is_active is_active: Bool,
 ) -> Result(Crew, CrewError) {
   use returned <- result.try(
-    sql.register(db, leader.uuid, crew_name, is_active)
-    |> result.map_error(Database),
+    case sql.register(db, leader.uuid, crew_name, is_active) {
+      // Crew name needs to be unique
+      Error(pog.ConstraintViolated(constraint: "crew_name_key", ..)) ->
+        Error(NameConflict)
+
+      // Other errors
+      Error(err) -> Error(Database(err))
+      Ok(rows) -> Ok(rows)
+    },
   )
 
   use row <- result.try(
···
     |> result.replace_error(NotFound),
   )
 
-  use leader <- result.map(
-    server_user.find(db, row.crew_leader)
+  use leader: User <- result.map(
+    user.find(db, row.crew_leader)
     |> result.map_error(UserError),
   )
 
···
   )
 }
 
+/// Assign a group of members to a crew.
+/// Nothing happens is a member is already assigned.
+///
+/// Returns all successfully assigned members.
 pub fn assign(
   db: pog.Connection,
   crew: Crew,
   members: List(User),
 ) -> Result(List(User), CrewError) {
-  let id_list = list.map(members, fn(member) { member.uuid })
+  let id_list = {
+    use member <- list.map(members)
+    member.uuid
+  }
 
   use returned <- result.try(
     sql.assign_members(db, crew.id, id_list)
     |> result.map_error(Database),
   )
 
-  use row <- list.try_map(returned.rows)
+  list.try_map(returned.rows, fn(row) {
+    use user <- result.map(
+      user.find(db, row.user_id)
+      |> result.map_error(UserError),
+    )
 
-  use member <- result.map(
-    server_user.find(db, row.user_id)
-    |> result.map_error(UserError),
-  )
-
-  User(
-    uuid: member.uuid,
-    role: member.role,
-    full_name: member.full_name,
-    email: member.email,
-    phone: member.phone,
-    is_active: member.is_active,
-  )
+    User(
+      uuid: user.uuid,
+      role: user.role,
+      full_name: user.full_name,
+      email: user.email,
+      phone: user.phone,
+      is_active: user.is_active,
+    )
+  })
 }

server/src/server/crew/sql.gleam

···
   AssignMembersRow(user_id: Uuid)
 }
 
-/// Runs the `assign_members` query
-/// defined in `./src/server/crew/sql/assign_members.sql`.
+///   Assign a group of members to a crew
 ///
 /// > 🐿️ This function was generated automatically using v4.6.0 of
 /// > the [squirrel package](https://github.com/giacomocavalieri/squirrel).
···
     decode.success(AssignMembersRow(user_id:))
   }
 
-  "insert into crew_membership as cm (
+  "--   Assign a group of members to a crew
+insert into crew_membership as cm (
     crew_id,
     user_id
 )
-
 values ($1, unnest($2::uuid []))
+
 on conflict do nothing
 returning cm.user_id;
 "
···
   )
 }
 
-/// Runs the `find_members` query
-/// defined in `./src/server/crew/sql/find_members.sql`.
+///   Find all members assigned to a determined crew
 ///
 /// > 🐿️ This function was generated automatically using v4.6.0 of
 /// > the [squirrel package](https://github.com/giacomocavalieri/squirrel).
···
     decode.success(FindMembersRow(id:, role:, full_name:, email:, phone:))
   }
 
-  "with member as (
+  "--   Find all members assigned to a determined crew
+with member as (
     select cm.user_id as id
     from crew_membership as cm
     where cm.crew_id = $1
···
   RegisterRow(id: Uuid, crew_leader: Uuid, crew_name: String, is_active: Bool)
 }
 
-/// Runs the `register` query
-/// defined in `./src/server/crew/sql/register.sql`.
+///   Register an new empty crew
 ///
 /// > 🐿️ This function was generated automatically using v4.6.0 of
 /// > the [squirrel package](https://github.com/giacomocavalieri/squirrel).
···
     decode.success(RegisterRow(id:, crew_leader:, crew_name:, is_active:))
   }
 
-  "insert into crew as c (
+  "--   Register an new empty crew
+insert into crew as c (
     crew_leader,
     crew_name,
     is_active
-) values ($1, $2, $3)
-
+)
+values ($1, $2, $3)
 returning c.id, c.crew_leader, c.crew_name, c.is_active;
 "
   |> pog.query

server/src/server/crew/sql/assign_members.sql

···
---    Assign a group of members to a crew
+--   Assign a group of members to a crew
 insert into crew_membership as cm (
     crew_id,
     user_id

server/src/server/seed/sql.gleam

···
 
   "-- 󰶚  Check if the user_account table is empty
 -- If it returns a least one row it means that the tables is not empty.
-select 1 as row_exists from public.user_account;
+select 1 as row_exists
+from public.user_account;
 "
   |> pog.query
   |> pog.returning(decoder)

server/src/server/user/sql.gleam

···
   )
 }
 
-/// Runs the `find` query
-/// defined in `./src/server/user/sql/find.sql`.
+///   Find details about an user
 ///
 /// > 🐿️ This function was generated automatically using v4.6.0 of
 /// > the [squirrel package](https://github.com/giacomocavalieri/squirrel).
···
     decode.success(FindRow(id:, role:, full_name:, email:, phone:, is_active:))
   }
 
-  "select
+  "--   Find details about an user
+select
     u.id,
     u.user_role as role,
     u.full_name,
···
   )
 }
 
-///   register an user
+///   Register an user
 ///
 /// > 🐿️ This function was generated automatically using v4.6.0 of
 /// > the [squirrel package](https://github.com/giacomocavalieri/squirrel).
···
     ))
   }
 
-  "--   register an user
-insert into public.user_account as u
-(full_name, user_role, password_hash, email, phone, is_active)
+  "--   Register an user
+insert into public.user_account as u (
+    full_name,
+    user_role,
+    password_hash,
+    email,
+    phone,
+    is_active
+)
 values ($1, $2, $3, $4, $5, $6)
 returning u.id, u.full_name, u.user_role, u.email, u.phone, u.is_active;
 "