Update docs, follow @roschaefer suggestions

- create command should be run with --date-format to be more human
  readable, and --template-file to use our template instead of migrate's
default
- rename migrations
- rename createdAt to migratedAt to remove ambiguity
- do not merge relationships for Location nodes as we don't want to
  create duplicate relationships
- use singular locationId as it's iterating one at a time

backend/README.md

@@ -120,7 +120,7 @@ you have to migrate your data e.g. because your data modeling has changed.
 {% tab title="Docker" %}
 Generate a data migration file:
 ```bash
-$ docker-compose exec backend yarn run db:migrate:create your_data_migration
+$ docker-compose exec backend yarn run db:migrate:create your_data_migration --date-format 'yyyymmddHHmmss' --template-file src/db/migrate/template.js
 # Edit the file in ./src/db/migrations/
 ```
 
@@ -132,7 +132,7 @@ $ docker-compose exec backend yarn run db:migrate up
 {% tab title="Without Docker" %}
 Generate a data migration file:
 ```bash
-$ yarn run db:migrate:create your_data_migration
+$ yarn run db:migrate:create your_data_migration --date-format 'yyyymmddHHmmss' --template-file src/db/migrate/template.js
 # Edit the file in ./src/db/migrations/
 ```
 

backend/src/db/migrate/store.js

@@ -35,7 +35,7 @@ class Store {
     const session = driver.session()
     const readTxResultPromise = session.readTransaction(async txc => {
       const result = await txc.run(
-        'MATCH (migration:Migration) RETURN migration {.*} ORDER BY migration.createdAt DESC',
+        'MATCH (migration:Migration) RETURN migration {.*} ORDER BY migration.migratedAt DESC',
       )
       return result.records.map(r => r.get('migration'))
     })
@@ -71,7 +71,7 @@ class Store {
             `
               MERGE (migration:Migration { title: $properties.title })
               ON CREATE SET migration += $properties,
-              migration.createdAt = toString(datetime())
+              migration.migratedAt = toString(datetime())
               RETURN migration
             `,
             { properties },

backend/src/db/migrations/20200123150110-merge_duplicate_location_nodes.js

@@ -24,19 +24,19 @@ export function up(next) {
             .records()
             .pipe(
               map(record => {
-                const { id: locationIds } = record.get('location')
-                return { locationIds }
+                const { id: locationId } = record.get('location')
+                return { locationId }
               }),
-              mergeMap(({ locationIds }) => {
+              mergeMap(({ locationId }) => {
                 return transaction
                   .run(
                     ` 
-                    MATCH(location:Location {id: $locationIds}), (location2:Location {id: $locationIds})
+                    MATCH(location:Location {id: $locationId}), (location2:Location {id: $locationId})
                     WHERE location.id = location2.id AND id(location) < id(location2)
-                    CALL apoc.refactor.mergeNodes([location, location2], { properties: 'combine', mergeRels: true }) YIELD node as updatedLocation
+                    CALL apoc.refactor.mergeNodes([location, location2], { properties: 'combine' }) YIELD node as updatedLocation
                     RETURN location {.*},updatedLocation {.*}
                   `,
-                    { locationIds },
+                    { locationId },
                   )
                   .records()
                   .pipe(

backend/src/models/Migration.js

@@ -1,5 +1,5 @@
 export default {
   title: { type: 'string', primary: true, token: true },
   description: { type: 'string' },
-  createdAt: { type: 'string', isoDate: true, default: () => new Date().toISOString() },
+  migratedAt: { type: 'string', isoDate: true, default: () => new Date().toISOString() },
 }