Update README.md (#207)

Created submission for STAC Index and slightly re-worded the summary to fix typos.

Author: zacdezgeo

README.md

@@ -24,17 +24,15 @@
 
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-**PgSTAC** is a set of SQL function and schema to build highly performant database for Spatio-Temporal Asset Catalog ([STAC](https://stacspec.org)). The project also provide **pypgstac** python module to help with the database migration and documents ingestion (collections and items).
+**PgSTAC** is a set of SQL functions and schema to build highly performant databases for Spatio-Temporal Asset Catalogs ([STAC](https://stacspec.org/)). The project also provides **pypgstac** (a Python module) to help with database migrations and document ingestion (collections and items).
 
-PgSTAC provides functionality for STAC Filters and CQL2 search along with utilities to help manage indexing and partitioning of STAC Collections and Items.
+PgSTAC provides functionality for STAC Filters, CQL2 search, and utilities to help manage the indexing and partitioning of STAC Collections and Items.
 
-PgSTAC is used in production to scale to hundreds of millions of STAC items. PgSTAC implements core data models and functions to provide a STAC API from a PostgreSQL database. As PgSTAC is fully within the database, it does not provide an HTTP facing API. The [Stac FastAPI](https://github.com/stac-utils/stac-fastapi) PgSTAC backend and [Franklin](https://github.com/azavea/franklin) can be used to expose a PgSTAC catalog. It is also possible to integrate PgSTAC with any other language that has PostgreSQL drivers.
-
-PgSTAC Documentation: https://stac-utils.github.io/pgstac/pgstac
-
-pyPgSTAC Documentation: https://stac-utils.github.io/pgstac/pypgstac
+PgSTAC is used in production to scale to hundreds of millions of STAC items. PgSTAC implements core data models and functions to provide a STAC API from a PostgreSQL database. PgSTAC is entirely within the database and does not provide an HTTP-facing API. The [Stac FastAPI](https://github.com/stac-utils/stac-fastapi) PgSTAC backend and [Franklin](https://github.com/azavea/franklin) can be used to expose a PgSTAC catalog. Integrating PgSTAC with any other language with PostgreSQL drivers is also possible.
 
+PgSTAC Documentation: https://stac-utils.github.io/pgstac/pgstac
 
+pyPgSTAC Documentation: https://stac-utils.github.io/pgstac/pypgstac
 
 ## Project structure