[翻訳]Correcting some minor typos and adding a link to SQL injection on Wikipedia for further reading.

- 対応する英語版は以下の通り
https://github.com/dsyph3r/symblog-docs/commit/fe965873b6b068e2e7a3df7701d16ea735680947
[翻訳]Changed command for generating repository class

- 対応する英語版は以下の通り
https://github.com/dsyph3r/symblog-docs/commit/07c52c11b18002d73c7a8491541cd4b62bfc28e7#diff-c2efd66fe28a9be549f9cc43daba53a2
[翻訳]Now uses composer for package manager

- 対応する英語版は以下の通り
https://github.com/dsyph3r/symblog-docs/commit/72f95e09412c0479350a79ddad99459259a7847f#diff-c2efd66fe28a9be549f9cc43daba53a2
[翻訳]remove old information regarding git deps

- 対応する英語版は以下の通り
https://github.com/dsyph3r/symblog-docs/commit/e5f49b78834aefac5ae8012008eab37d60f4c8fc#diff-c2efd66fe28a9be549f9cc43daba53a2
[翻訳]add comment to code example

- 対応する英語版は以下の通り
https://github.com/dsyph3r/symblog-docs/commit/13929b7c8fb151ebd77e4c36e1a953f031588bd9
[翻訳]Renaming getEntityManager to getManager

- 対応する英語版は以下の通り
https://github.com/dsyph3r/symblog-docs/commit/c480a802c112594e535bbbdbcc8abdc0877281e6
Merge pull request #5 from kseta/fix-cp4

[翻訳][Part4]42ad0ad4c5まで更新