[DESIGN][m]: add roadmap section.

DESIGN.md

@@ -1,5 +1,73 @@
 # Design Notes
 
+## Roadmap
+
+General comment: let's do "README" (docs) driven development here.
+
+* [x] [show] Local functionality for Frictionless datasets with CSV #528
+  * [x] Move in new work (portal-experiment) into portal.js and refactor https://github.com/datopian/portal.js.bak/issues/59
+* [ ] [show] Uber Epic covering all functionality **See below**
+  * [ ] [show] README only + data datasets (don’t have to be frictionless)
+    * (?) Graphs direct in README with say visdown …
+  * [ ] [show] SQL interface to the data (alasql or sql.js … https://github.com/agershun/alasql/wiki/Performance-Tests)
+  * [ ] file/resource subpages ... (for datasets with lots of resources)
+* [ ] Docs **80% analysed** #
+* [ ] Create portal components and library i.e. have a Table, Graph, Dataset component
+  * [ ] publish to @datopian/portal
+  * [ ] Examples
+* [ ] Catalog functionality **20% analysed**
+ 
+## [uber][epic] Show functionality for single datasets
+
+### Features
+
+* Elegant
+* Description (README/Description)
+* Data preview and exploration (for tablular)
+  * Basic: some sample data shown
+  * Data exploration v1: filterable
+  * Data Exploration v2: can do sql etc ...
+* Graphs / visualization
+* Validation: this row does not match schema in column X
+* Summarization e.g. this columns has this range of values, this average value, this number of nulls
+
+### Dataset structure support (in rough order of priority / like implementation)
+
+* Frictionless
+* Plain README (with frontmatter)
+* README (no frontmatter) and LICENSE file (?)
+
+Data has roughly two dimensions that are relevant
+
+* Format
+  * CSV
+  * xlsx
+  * JSON
+  * ...
+* Size
+  * Small: < 5mb (can just load inline ...)
+  * Medium < 100mb
+  * Large < 5Gb
+  * xlarge > 5Gb
+
+* TODO: How does show/build work with remote files e.g. a resource ...
+
+  ```
+  path: abc.csv
+  remote_storage_url: s3://.../.../.../
+  ```
+
+  Options:
+
+  * We clone the data into path locally ...
+    * Possible problem if data is big ...
+  * Load data direct from remote_storage_url (as long as supports CORs)
+
+
+
+
+## Architecture
+
 Portal.js is a React and NextJS based framework for building dataset/resources pages and catalogs. It consists of:
 
 * React components for data portal functionality e.g. data tables, graphs, dataset pages etc