change migrate to CB-CSV section

Author: evanwill

docs/advanced/migrate-to-csv.md

@@ -0,0 +1,59 @@
+---
+title: Migrate CB-GH to CB-CSV
+parent: Advanced
+nav_order: 14
+---
+
+# Migrate CollectionBuilder-GH project into CollectionBuilder-CSV
+
+Sometimes you will have created a prototype collection using CB-GH or CB-Sheets and find that you would like to continue developing it in the more robust CB-CSV template. 
+It is straight forward to migrate your project by updating your metadata and copying over your objects into a new CB-CSV project (in most cases this is much easier than updating the template in your existing repository!).
+
+First, create a new project repository from [CB-CSV template](https://github.com/CollectionBuilder/collectionbuilder-csv).
+
+## Copy Objects
+
+Copy the files in your CB-GH project "objects" folder.
+Paste them into the "objects" folder in your new CB-CSV project.
+
+Open a terminal and run `rake generate_derivatives` (see [Objects Derivatives for more info](/cb-docs/docs/objects/derivatives/)).
+
+In ".gitignore", comment out `objects/`.
+
+Commit the objects into the repository.
+
+## Update Metadata
+
+Open your existing CB-GH metadata in Sheets or OpenRefine.
+You will need to add [CB-CSV's technical metadata fields](https://collectionbuilder.github.io/cb-docs/docs/metadata/csv_metadata/#strongly-suggested-fields), which can be done using equations to transform your existing columns (see [Recipes for generating Object Location Fields](/cb-docs/docs/metadata/object-paths/)).
+
+- "display_template": from your CB-GH "format" field, create a new column "display_template". Edit all "image/jpeg" to `image`, "application/pdf" to `pdf`, "
+- "object_location" From your CB-GH "filename" field, create a new column "object_location". 
+    - For items with a local filename, put `/objects/` in front of the filename value.
+    - For items with a full URL, leave as is.
+    - For items with "youtubeid" or "vimeoid", use the id to create the full youtube link in "object_location".
+- Set up "image_small" and "image_thumb" from "filename".
+
+## Transfer Configurations
+
+Carefully compare the various configuration files in your CB-GH project with the default ones in your new CB-CSV project.
+CB-CSV will have slightly MORE options than the CB-GH versions, so they can not be just copied over. 
+Transfer the configurations values from your CB-GH project into CB-CSV where they match.
+Check over these files:
+
+- "_config.yml"
+- "_data/theme.yml"
+- Configs in "_data/": "config-browse.csv", "config-map.csv", "config-metadata.csv", "config-nav.csv", "config-search.csv", "config-table.csv", and "config-theme-colors.csv"
+- "_sass/_custom.scss"
+
+## Transfer Content Pages and Customizations
+
+Carefully check over any pages that you have directly customized or added content to.
+Most commonly this would include:
+
+- "pages/about.md"
+- "_layouts/home-infographic.html"
+
+## Setup to Deploy with GitHub Actions
+
+For the [docs for deploying using GitHub Actions](/cb-docs/docs/deploy/actions/).