add user-project relation and role-based filtering

water-api/sql/add_user_project_relation.sql

@@ -0,0 +1,27 @@
+-- ============================================================================
+-- Add project_id to users table
+-- This allows assigning a specific project to OPERATOR users
+-- ADMIN users don't need a project assignment (can see all projects)
+-- ============================================================================
+
+-- Add project_id column to users table
+ALTER TABLE users 
+ADD COLUMN project_id UUID REFERENCES projects(id) ON DELETE SET NULL;
+
+-- Add index for better query performance
+CREATE INDEX idx_users_project_id ON users(project_id);
+
+-- Add comment
+COMMENT ON COLUMN users.project_id IS 'Assigned project for OPERATOR users. NULL for ADMIN users who can access all projects.';
+
+-- ============================================================================
+-- Verify the change
+-- ============================================================================
+SELECT 
+    column_name, 
+    data_type, 
+    is_nullable,
+    column_default
+FROM information_schema.columns 
+WHERE table_name = 'users' 
+  AND column_name = 'project_id';